MODERN HYDRONICS 2014 autumn
Design fundamentals
Ramping Up System performance How To Use
pumps For
zoning COOLING OPTIONS THE LANGUAGE OF ENERGY AND POWER a publication of
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MODERN Hydronics a supplement of Heating Plumbing Air Conditioning Magazine HPAC Magazine 80 Valleybrook Drive, Toronto, ON M3B 2S9 TEL: 416.442.5600 FAX: 416.510.5140 www.hpacmag.com Editor Kerry Turner (416) 510-5218 KTurner@hpacmag.com assistant editor Associate publisher Account manager sales & marketing coordinator Art Director Market Production Manager Circulation Manager PUBLISHER
Patrick Callan (416) 442-5600, ext. 3524 David Skene (416) 510-6884 DSkene@hpacmag.com Stephen Kranabetter (416) 510-6791 SKranabetter@hpacmag.com Kim Rossiter (416) 510-6794 KRossiter@bizinfogroup.ca Sandy MacIsaac (416) 442-5600, ext. 3242 Barb Vowles (416) 510-5103 BVowles@bizinfogroup.ca Selina Rahaman (416) 442-5600, ext. 3528 SRahaman@bizinfogroup.ca
Contents MH4
Energy and Power
Getting the terminology right. By John Siegenthaler
MH6 Ramping Up System Performance
How do you determine the efficiency of the heating system you are recommending to a customer? By Mark Norris
MH14 HYDRONIC PRODUCT SHOWCASE
Peter Leonard (416) 510-6847 PLeonard@hpacmag.com
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MH21 COOLING OPTIONS
FOR HYDRONIC APPLICATIONS
By Mike Butler
Take the time to understand the fundamentals. By Steve Goldie
Design option uses pumps to control flow. By Mike Miller
MH24 Complex times call for drastic measures
MH26 Less Is More
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MODERN HYDRONICS
Autumn 2014
| MH3
7/17/2014 11:36:21 AM
>> Terminology
Energy & Power The terms are different but related
M
ost HPAC readers deal with units such as Btu/hr, kilowatts, °C and many others on a daily basis. For the most part, you use valid units to describe physical quantities. For example, you know that flow rate is measured in gallon per minute (gpm), and not gallons. You also know that temperature is expressed in °C or °F, and not in therms. However, when it comes to the difference between energy and power, our industry tends to get sloppy with its terminology. For example, some of us might tell a potential customer how a new geothermal heat pump system could reduce their “power bill.” We might also describe the choice between a couple of boilers as the 75 000 Btu model versus a 100 000 Btu model. While I am sure that these statements each convey a valid point, they are both incorrect from a technical point. They are using invalid units for the physical quantities being discussed. For example, suppose I told you “it is 5.5 hours between where I live and Toronto.” I am using a unit of time to describe a distance. It might take 5.5 hours at an average speed of 60 miles per hour to drive the distance of 330 miles from my house to Toronto. However, it might also take six hours if I average 55 mph, or 4.7 hours if I average 70 mph (and manage not to get pulled over for speeding). The speed I drive does not change the distance. So, if someone wants to know how far it is from my house to Toronto, ON a valid answer would have units of distance (330 miles). For that matter, it would also be technically valid to tell someone it is about 1 742 400 feet, or even about 53 108 352 centimeters from my house to Toronto. Granted, very few people would have any feel for that distance when expressed in either of these units, but nevertheless, both units are valid for describing distance. TERMINOLOGIST Back in the 1970s, I had a physics professor who was as methodical as a computer and not the least bit tolerant of improper usage of physics terminology. He revered the precise mathematic definitions used to define physical quantities. He was also very careful in using words that at times could only convey partial meaning to physical quantities such as velocity, acceleration, frequency, weight and temperature. The precision he used made a deep impression on me. It also clarified these concepts and removed the apprehension that many MH4 | autumn 2014
people seem to have over almost anything associated with physics. Two of the most important principles in all of physics are energy and power. They are also two of the most widely used (and misused) concepts in the HVAC industry. Most physics textbooks define energy as the ability to do work. At first, this sounds like a pretty loose definition. After all, following a good night’s rest and hearty breakfast, most of us think that we have the ability to do work. The key is in that last word - work. In physics, work is mathematically defined as the multiplication of a force times the distance over which the force acts. For example, if you lifted a 20 pound weight, three feet above where it was resting, you would have imparted 3 ft x 20 lb. = 60 ft•lb of mechanical energy to that object. Thus a ft•lb (pronounced foot pound) is a unit of energy (albeit a fairly small amount). As such, it can be converted to any other unit of energy. For example: 778.2 ft•lb = 1 Btu The unit of ft•lb is most commonly associated with mechanical energy, whereas the unit Btu is usually associated with thermal energy. However, mechanical energy can be converted to an equivalent amount of thermal energy. It is like comparing the unit of kilometer, which is commonly used to express distances that we drive or bike, to nanometers, a unit of distance often used to describe the width of conductor paths in microprocessors. Both are units of distance and each happens to be more commonly used for certain types of distance measurements. In hydronics the unit of ft•lb is concealed in the definition of “head.” We commonly state the head produced by a circulator in units of feet. This comes from the following ratio:
ft • lb = ft lb Since the unit of lb appears in the top and bottom of the fraction, it mathematically cancels out and we can just state pump head in units of feet. However, I still contend that the best understanding of head comes when it is thought of as the number of ft•lbs of mechanical energy added to each lb. of fluid that passes through the circulator. POWERFUL THOUGHTS In physics, power is defined as the instantaneous rate of energy transfer. Although the word energy is in the definition of power, the word rate makes the concept of power as different from energy as speed is from distance.
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In the HVAC trade we are usually concerned with rates of energy flow, rather than a quantity of energy. The thermal output of a boiler is a rate, as is the output from a heat emitter and the heat loss of a building. Some of the most common units for power in our trade are: Btu/hr, watt and kilowatt. In North America, the units of watt and kilowatt are most often associated with electrical power. However, they are just as valid for describing the rate of heat output from a boiler and are commonly used as such in Europe. Thus, a European installer asking his wholesaler for a 21 kW gas-fired boiler is just as common as an installer in North America asking their supplier for a 72 000 Btu/hr boiler. Just have a look at the thermal ratings of boilers, heat pumps or heat emitters shown on the websites of European manufacturers. North America is about the only place on earth that lists thermal ratings in units of Btu/hr. The conversion factor between kilowatts and Btu/hr is used so commonly that it is worth memorizing: 1 kW = 3413 Btu/hr They are not the same thing. The relationship between energy and power is pretty simple: Energy = power x time It is analogous to the relationship: Distance = speed x time. Distance and speed are related, but they are not the same thing and the same applies to energy and power. If a device supplies power at one kilowatt and maintains that power for one hour, it will have supplied: Energy = 1 kW x 1 hr = 1 kWhr The unit kwhr is also sometimes abbreviated as kWh. If a heat emitter dissipated heat at a rate of 250 watts for three hours it will have supplied the following amount of energy to the room: Energy = 250 w x 3 hr = 750 whr = 0.75 kWhr A kWhr is a unit of energy, and as such, can be converted to any other unit of energy. For example 1 kWhr = 3413 Btu The vast majority of us buy electrical energy from a utility and we are charged based on the number of kWhr of energy we have used in that billing period. The term “power bill” is not correct. It is in fact an energy bill that we receive. FIGURE IT OUT Recognizing the relationship between units and the physical quantities they represent can be helpful. For example, take a look at Figure 1. I took this photo in the mechanical room of a hotel in Cologne, Germany. This device was connected to a pipe and had an odometer-like totalizer that gave a reading in MWh (e.g. Megawatt•hours). It also had a scale indicating “Temp Diff” (e.g. temperature differential) in °C. Inside the glass cover was an assortment of springs, gears, shafts, and linkages that would make a clockmaker proud. So what do you think it is? Well, it gives a readout of MWh (megawatt•hours), which is a large unit of energy, so it must be an energy meter. The connecwww.hpacmag.com
Figure 1
tion to the pipe measured flow rate and the multiplication of flow rate times temperature differential is directly proportional to energy. The system’s caretaker confirmed my suspicion. He also told me that this thermal energy meter has been in place and operational since the 1960s. No wires, no batteries, no microprocessors, just an elegant mechanical integrator mechanism. BE A PRO Over the years I have seen technical publications, product literature, advertisements and even materials issued by ASHRAE, that have described energy, or energy savings, using terms like kilowatts, or kilowatts per hour. The former is a unit of power and the latter is undefined. Sadly, few North Americans would recognize these errors, or even care. But caring about details, even when it is a seemingly small difference, is what makes a professional different from the average Joe Wrenchturner. So be a pro and use the right terminology and the right units when dealing with energy or power. I will appreciate it, and so would my old physics professor. <> - John Siegenthaler John Siegenthaler, P.E., is a mechanical engineering graduate of Rensselaer Polytechnic Institute and a licensed professional engineer. He has over 34 years experience in designing modern hydronic heating systems. He is also an associate professor emeritus of engineering technology at Mohawk Valley Community College in Utica, NY.
MODERN HYDRONICS
autumn 2014
| MH5
>> Efficiency
Ramping Up System Performance
H
ow do you determine the efficiency of the heating system that you are recommending to a customer? It is an important question that comes up regularly, but there is no simple answer. The simple answer would be the published boiler efficiency, right? Simple, maybe, but probably not correct because the published efficiencies will rarely be an accurate representation of real system efficiency. The testing that residential boilers undergo for annual fuel utilization efficiency (AFUE), or the BTS-2000 tests that commercial boilers are subject to, are controlled environment tests, intended to provide a base line for all appliances in that category. These appliances are tested to the same conditions, under the same standard, so you can compare them all with equal data. Unfortunately, it is not possible to represent all of the variables that our heating systems are exposed to in what is essentially a laboratory test. There are also several things we can do to make our system efficiencies better that the tests do not consider. So where do we get the information required to determine our systemâ&#x20AC;&#x2122;s efficiency? Go to the source for that installation. Look at the design, the equipment and how you intend on using them. Under the right conditions you can potentially exceed the AFUE or other standard tests in the field. Other times you may not even get close to the rated efficiencies. Mostly it comes down to the designer or contractor installing the system. In the case of a retrofit, the equipment that will remain will also influence the efficiencies. When designing or assessing a new or retrofit system the place to start is the heat emitters. Higher temperature emit-
ters will be less efficient than lower temperature types. Fin tube heat emitters, for example, require hotter water and more energy to supply the same amount of heat to the space in comparison to lower temperature radiant floor designs. Older fan coils will require higher temperature water than newer fan coil designs, so the same logic applies (see Figure 1). It starts with how hot you need to get the water to provide enough heat on a design day (coldest day of the year). Do not make the mistake of thinking that you will need to supply 8285C water to fin tube heat emitters for them to function. You can get a lot of heat out of a higher temperature emitter at lower temperatures if you have enough emitters. The same applies to most other types of heat emitters as well. The heat emitter manufacturers will have a chart or table that will give you a method to determine how much heat their product will deliver at lower than the published design temperatures and flow rates. With any hydronic heating system, outdoor reset temperature controls can adjust the system water temperature required to heat the space on the design day to the lower temperatures needed for a warmer winter day. Remember, heat moves from a warm place to a colder place faster with a greater temperature difference, so the building will lose heat faster on a colder day. Building envelope efficiency is also a factor in the rate of heat loss. A building with good insulation and tight windows will lose heat more slowly than one with poor insulation and leaky windows on a day of the same outdoor temperature. Because the heat emitters do not change
Figure 1 Fan coils for condensing boilers Larger coil with greater HX surface area.
Figure 2 Heating Curve
MH6 | autumn 2014
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from warmer to colder days, we compensate for that greater heat loss by increasing the water temperature, or reducing it on warmer winter days when the heat loss is less. That is what outdoor reset does automatically (see Figures 2,3). The three to one rule states that for every three degrees C that the average heating system temperature is reduced, one per cent less fuel will be consumed. This works with all hydronic heating systems. In reality we typically only need our design day temperatures for about two to four per cent of the heating season almost everywhere in Canada. How many contractors change the factory reset heating curve settings? I find that nearly half of the students in my classes do not change the heating curve values because they do not understand what it does, or how to adjust them correctly. If I apply that same outdoor reset control to a high efficiency condensing boiler, I also get the added value of the condensing process returning energy that would normally be lost to outside through the venting system back into the heating system. When the flue gas changes from a vapour to a liquid (condensate) it has to give up a bunch of energy. When that happens at the boiler’s heat exchanger, that energy can be transferred to the heating system (see Figure 4). How much energy is that? It is approximately 8095 Btus per USG of condensate. The deeper the reset, the more condensate can be produced and the more energy is recovered (see Figures 5a,5b). Measure or calculate the amount of condensate coming from the boiler to determine how much energy is recovered for determining efficiency. The efficiency numbers from your combustion analyzer only tell part of the story. Your combustion analyzer only sees the sensible heat (non-condensing) portion of the process. However, your combustion analyzer does provide more information about the boiler’s efficiency than simple efficiency percentage.
If you are using a burner that requires combustion setup, how much excess air that is introduced will change the CO2 percentage and consequently the dew point. Newer premix design burners require little or no setup because they can be factory calibrated. Even if the boiler’s burner is preset, you still need a combustion analyzer to verify the machine is working as designed and is operating safely. Without combustion analyzing you are driving a car with no front window. Dew point temperature will affect when and how much condensate we get from a condensing boiler and therefore effect efficiency (see Figure 6). The higher the C02 in the flue gas, the higher the dew point, so you can start condensing higher return temperatures. If we lived in a perfect world, we could set our burners for 0 per cent excess air (Lambda 1.0, or Stoichiometric) and get the higher efficiency at slightly higher flue gas temperatures. Altitude, humidity, dirt and so on, make it necessary to add excess air so we do not potentially produce CO, which is toxic. As shown earlier, adding too much excess air will lower the efficiency. Another way to control efficiency in a condensing boiler is to increase the system delta T (the difference between the supply water and the return water to the boiler). Because the rate of condensate is based on the boiler return water temperature, not the supply water temperature, a larger delta T between supply and return can increase the boiler’s efficiency by returning the water to the boiler below the dew point. You can increase the delta T simply by reducing the pumping speed. If we build a system around a standard 15C delta T with a design day supply temperature of 71C the water will return at 56C, higher than the dew point of approximately 54C at 10 per cent CO2 in the flue gas. If we increase the delta T to 20C or 25C we can get the return temperature down to 51C, or 46C respectively, below the dew point. This will potentially get the boiler condensing even for those few design days (see Figure 7).
Figure 3 Heating curve screenshot
Figure 4 Vapour to liquid
continued on pMH8
• Water vapour turns to liquid when it is reduced in temperature. • Energy is released when vapour turns to liquid.
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MODERN HYDRONICS
autumn 2014
| MH7
>> Efficiency continued from pMH7 Oversizing the boiler will cause boiler short cycling on milder days and that is a big efficiency robber. Undersizing the boiler can be just as bad because boilers with modulating burners will spend more time at a higher burner output. We can typically add between 1C (at low fire) and 12C (at high fire) to the return water temperature value when calculating the flue gas Figure 5a Condensate flow rate
temperature for wall hung condensing boilers, depending on the burner’s actual modulation output. Once you know the estimated dew point from the excess air calculation you can determine the amount of condensate based on the return water and boiler modulation calculation and therefore the energy being recovered. From this we can see that a condensing boiler with a lower firing rate that is not short cycling will provide higher efficiencies. When I talk about oversizing, I am talking about the miniFigure 5b Formula to convert, grams of condensate to BTU’s of energy recovered Grams x kWh = grams of condensate Grams of condensate / 3780 = USGal of condensate USGal of condensate x 8095 = BTUs The data shown is for a 985 kW boiler
The data shown is for a 985 kW boiler
~40 °C Return Water Temperature
~30 °C Return Water Temperature
~75 x 985 = 73 875
~102 x 985 = 100 470
73 875 / 3780 = 19.5
100 470 / 3780 = 26.6
19.5 x 8,095 = ~157 852 BTUs
26.6 x 8095 = ~215 327 BTUs
continued on pMH10
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MH8 | autumn 2014
MODERN HYDRONICS
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>> Efficiency continued from pMH8 mum output not really the maximum output. Boilers with modulating burners and efficient burner algorithms will modulate to find the lowest firing rate needed to do the job. But the minimum output is the lowest that burner can go and if Figure 6 C02 and Dew Point
Figure 7 ASHRAE Design Day
Figure 8 Boost Chart
the load is smaller than that, we get short cycling under partial load conditions, which occur most of the heating season. Increasing the system mass with a buffer tank or more heat emitters can give us extra stored load capacity for systems using low mass boilers. This adds to system installation costs but is worth doing under some conditions. So, are bigger turndowns better? Not necessarily. More excess air is typically required for lower firing rates to maintain flame stability. The larger the turndown, the more excess air is required. We have already seen that higher excess air makes it harder for the boiler to produce the condensate that is the result of the higher energy recovery. This results in a strange little relationship that ends up with less fuel burned but what is burned is burned less efficiently. How do we increase system turndown without adding too much excess air? Letâ&#x20AC;&#x2122;s look at this scenario. Our building has a turndown between the design day load and the base load (smallest load we still need heat for) of eight to one. The boiler design has a functional turndown of five to one. To install a boiler that can supply enough heat for the coldest day, it will be oversized on the warmest day that heat is required by roughly eight per cent. That may lead to boiler short cycling. However, the total boiler turndown can be increased to 10 to one if two smaller boilers are connected with a cascade control that can efficiently operate them as a team. This requires communication between the boilers and the cascade so the cascade can know how hard each boiler is working. Depending on the cascade controlâ&#x20AC;&#x2122;s functionality, on mid level loads you could operate two boilers in low fire instead of one boiler at a higher firing rate and reduce the net flue gas temperature. This keeps the flue gas temperatures further below the dew point, which will produce more condensate. Because the lowest firing rate is 1/10 of the maximum, less heat is provided without short cycling on partial load days. Multiple boilers will cost more to operate and install than a single boiler because of the extra pumps, controls, piping and so on, but this can usually be offset by the higher condensate volumes and reduced short cycling that results when multi boiler designs are applied to buildings with larger turndown loads. It also provides a level of redundancy in case of equipment failures. Looking at the maximum boiler output compared to load, a boiler system that has a larger output than design will provide extra capacity for morning boost to recover from the setback faster (see Figure 8). This also requires enough emitter capacity to take that capacity and a control that can provide a boost function. (This is not the optimization algorithm that some setback controls have; this is the ability to increase the outdoor reset set point by a value for a short time during morning warm up. Most optimization logic starts the system earlier or later depending on previous history). continued on pMH12
MH10 |
autumn 2014
MODERN HYDRONICS
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>> Efficiency continued from pMH10 Up until now I have focused on the combustion and thermal heat transfer efficiencies. Electrical efficiencies are also part of the equation. It is estimated that pumping accounts for up to one fifth of the electrical energy used in a hydronic heating system. One pump manufacturer estimates that 99 per
cent of pumps in commercial buildings are oversized. When you consider that most of the year we are under partial load conditions this makes the oversizing worse. As we include more zoning in our systems the volume of water circulated changes. The use of high efficiency vari-
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MH12 | autumn 2014
able speed pumps can reduce the electrical consumption for pumping by up to 75 per cent. While I believe that variable speed pumps are a wise consideration for a lot of pumping needs, they are not a complete solution. Changing the flow through the heat exchanger of a modulating boiler will tend to lead to burners hunting to find the stable output. This is because a boiler sees varying flow as a varying load. This is another good reason to pipe systems in a primary secondary configuration. A fixed speed circulator through the boiler stabilizes the flow so the burner can be more efficient in its modulation, and selected variable speed pumps in zones where zoning requires flow changes to maintain delta T through the heat emitters. In summary, remember the follwing points and you will be well on your way to delivering truly efficient systems: • Lower temperature heat emitters set up to operate with a larger delta T and flow rates that can adapt to zoning flow changes will get us lower return temperatures. • Higher CO2 levels in our flue gas will get us higher dew points. • Lower return water temperatures and a higher dew point will lead to higher efficiencies for the hydronic system. • Higher mass systems with more heat emitter capacity and burners sized for minimum loads with extra capacity and control for morning boost will reduce short cycling. In addition to the topics covered here, efficient piping layouts, pipe insulation, and water treatment, will also affect the overall fuel, thermal and electrical efficiencies of the system, but these are topics on their own. <> - MARK NORRIS Mark Norris is a technical instructor with Viessmann Manufacturing Company Inc.
MODERN HYDRONICS
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The Schluter-Bekotec is a modular screed system best suited for hydronic radiant heating applications. It reduces thermal mass, provides thermal insulation, and allows for hydronic radiant tube application without fasteners. The basis for this system is a studded polystyrene screed panel that is placed directly over any load-bearing substrate. The studs form a grid pattern with a distance of three inches between studs to accept hydronic heating tubes ⅜-in. to ⅝-in. O.D. www.schluter.com
The Freedom radiator by Jaga Climate Systems features an aluminum grill with black rubber lining and a compact design. Designed for small and sustainable spaces, this radiator works best when using heat pumps and new heating techniques at very low water temperatures. Also suitable for condensing and noncondensing cooling, all Freedom radiators are
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MH14 | autumn 2014
MODERN HYDRONICS
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Delivering up to 95.2 per cent AFUE, the ECO Boiler from WeilMcLain Canada is designed to provide optimum heating and save contractors time. The ECO’s stainless steel fire tube heat ex-
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continued on pMH16 MODERN HYDRONICS
autumn 2014
| MH15
>> Products continued from pMH15
KN-Series gas-fired direct vent cast iron condensing boilers by Advanced Thermal Hydronics combine the high 99 per cent efficiency and small footprint of modern low mass boilers with the long life and reliability of cast iron boilers. Available with inputs ranging from 200 to 3000 MBH, KN-Series boilers are ideal for commercial or large residential applications, including apartment complexes, institutional buildings with radiant heating systems, water source heat pumps and snow melt. www.hydrotherm.com The MagnaTherm from Laars is a 95 per cent thermal efficiency modulating-condensing boiler or volume water heater, available in two, three and four million Btuh sizes. MagnaTherm offers a 5:1 turndown, small footprint, multiple voltage options, a stainless steel heat exchanger, and a slim vertical design with removable top section. The boiler also features an advanced vari-prime pump control that matches boiler-firing rate to pump flow. www.laars.com
The EPJ Indirect Tank Series from Allied Engineering features 444 stainless steel tank and coil. A polypropylene plastic casing gives the tank a durable dent and scratch resistant finish. The EPJ tank is available in 40 and 56 gallon models. The high recovery rate makes the tank a great fit for any hydronic heating system. www.alliedboilers.com
continued on pMH18 MH16 |
autumn 2014
MODERN HYDRONICS
www.hpacmag.com
>> Products continued from pMH16
Uponor North America has designed six new ProPEX lead-free brass CPVC Adapter Fittings for transitioning from CPVC to PEX in commercial plumbing and hydronic distribution piping systems. The fittings, which are available in 1¼-in., 1½-in. and 2-in. sizes, are offered in a spigot and a socket adapter. All feature Uponor’s ASTM F1960 ProPEX expansion system for connecting to PEX piping. www.uponor.ca
The Bosch Heatronic 4000 controls and monitors both condensing and non-condensing commercial boilers that have modulating, single-stage, two-stage and dual fuel burners. Designed and configured with commercial and light industrial installers in mind, the control has a Bosch/Buderus boiler menu selector Lochinvar has launched its FTXL Fire Tube
with the entire range of condensing and non-
RBI’s Infinite Energy2 (IE2) uses a radial vari-
Boiler for light commercial applications. With
condensing, stainless steel, cast iron and cast
able circulation stainless steel heat exchanger
five models ranging from 399 999 to 850 000
aluminum commercial boilers with individual
for maximum heat transfer and operating effi-
Btuh, this boiler delivers up to 10:1 turndown
inputs from 215 to 5443 MBH.
ciencies of up to 98 per cent. The IE2 is avail-
and up to 98 per cent thermal efficiency. With
www.boschheatingandcooling.com
able from 199 to 1000 MBH and up to 20:1
a redesigned multi-color LCD interface and
firing rate modulation per unit. Units are PVC,
many new control features, the operating sys-
The Presscon tailpiece with union nut is de-
polypropylene and stainless steel vent capable.
tem offers the option of direct integration into
signed to make installation and maintenance
They can be installed in a multiple unit master/
a building automation system through commu-
of Caleffi components fast, easy and efficient.
member configuration (eight units max) using
nication protocols such as Modbus or BACnet.
The fitting creates a leak-proof seal and is
its on-board control. www.rbiwaterheaters.com
www.lochinvar.com
available in ¾-in. press x 1-in. female union nut, which fits many Caleffi components with
MH18 | autumn 2014
Armstrong Fluid Technology has introduced Main-
1-in.
tenance-Free (MF) versions of its S&H Circula-
thread. The tailpiece is com-
tor line and the Seal Bearing Assemblies (SBA)
patible within a working tem-
used to service them, which eliminates the need
perature range of 0 to 250F
for oiling. The line is available as an additional
for up to 50 per cent glycol
option alongside the traditional sleeve bearing
mixtures and pressure rated
designs. The SBAs are compatible with many
to 200 psi. The fitting meets
competing circulator models that require mainte-
2014 low-lead requirements.
nance. www.armstrongfluidtechnology.com
www.caleffi.com
MODERN HYDRONICS
male
union
(straight)
www.hpacmag.com
Modern Hydronics
IBC has released eight new boilers including the DC Series Combi Boiler, which combines domestic hot water and space heating in a single compact design. The boiler condenses continually in both space heating and domestic hot water modes. A dual two in one, back-to-back heat exchanger eliminates the need for a diverter valve and secondary domestic hot water plate heat exchanger. Features include outdoor reset technology and unique “self learning” ECOmode for greater DHW efficiencies. www.ibcboiler.com Viega’s new zone valves are designed to make installing and operating radiant heating and cooling easier. Available with multiple connection types, these zone valves integrate into hydronic systems and adapt to nearly any connection type from Viega ProPress or Viega PEX Press. Features include high flow capacity and low power consumption. www.viega.com
HeatLink’s line of pre-engineered boiler panels is designed for use with Weil-McLain and Viessmann condensing, high efficiency, wallmounted boilers. The panel is a prefabricated hydronic distribution system that streamlines installation times. The panels provide multi-zone capability and are available with mounting and piping options to suit boiler room layouts, and require minimal space. www.heatlink.com
The System Commander HVAC Control Series integrates entire heating, cooling, humidification and ventilation systems into one central network, which is easily accessible by smartphone or any mobile device. Its modular design allows you to scale or expand the system to fit any HVAC mechanical installation. Multiple functions, like domestic hot water (DHW) control, mixing, snow melt, OAT, CO2 or humidity detection and much more, can be combined and integrated for automatic recognition and command execution. www.thermomatrix.com www.hpacmag.com
MODERN HYDRONICS
autumn 2014
| MH19
>> Cooling
Options For Hydronic Applications
C
ooling in a hydronic heating environment suggests that the heating is already present. In the perfect total system design, heat is delivered from the floor and cooling from the ceiling or high wall. This approach also carries the potential to eliminate the need for ductwork. How do we handle cooling for these areas if hydronic cooling is not included in the design or in a retrofit situation? When adding or replacing cooling to a house the buyer has many choices with an “A” coil split system. Each manufacturer offers a variety of models depending on the price paid and the efficiency of the machine – typically a good/better/best scenario with the latter costing the most money and delivering the highest efficiency or lowest operating cost. Another benefit to the higher efficiency air conditioner is a much quieter system.
Cooling terminology Residential cooling refers to any space used for a family dwelling — one that requires human comfort only, and not professional accoutrements. For example, a house used as a doctor’s office is considered commercial use. Commercial cooling refers to any non-residential cooling environment. Some conditions to be considered are (i) building type, (ii) materials used, like brick, stone, wood siding, aluminum/steel panels or concrete panels, (iii) various types of insulation in walls and ceilings and the insulation’s R values, (iv) exposure to sun and wind, and sun blockage from trees or other buildings, (v) amount of glass used in square feet, type of glass (single, double, triple plate or thermo pane) and any special features, such as reflective ability or E-type glass. MH20 | autumn 2014
Are there any other solutions? Yes, in fact there are other choices. 1. A fan coil system consists of a fan box/a coil box and a filter box. Mounted indoors, this is connected to a condensing unit outdoors. Ductwork and diffusers are the hook up to deliver the conditioned air to the various rooms. It is also referred to as a split air conditioning system. 2. Ductless systems were first introduced in the mid 1980s, to high-end, hot water heated houses where the only previous method of cooling had been a window fan or a window mounted air conditioner. The window mounts were relatively small in size (and capacity) due to window size constrictions. All window units were considered noisy, especially in bedrooms. The significant difference with the ductless is the coil (evaporator) is located in the room being cooled – i.e. bedroom or living room. The humidity reduction is instantaneous. You can walk into a room at 85F, turn on the ductless system and instantly feel cool air within the room as well as immediate humidity removal. Within 10 to 15 minutes the room will feel very comfortable. The sound levels are also extremely low. An added bonus to the ductless system is the low cost to operate the system compared to the conventional split air conditioner. The applications for ductless have grown from residential all-purpose, hot water heated sites to targeting individual rooms, such as a home office, a sunroom, or a third floor addition (that last one, impossible to get ductwork to). One manufacturer offers a wall mounted version disguised as a mirror or integrated into a picture. For larger homes in downtown areas, where outdoor space is at a premium, the option could be to have multiple indoor units (up to eight) all attached to one outdoor unit. These new options are available in a ductless heat pump version.
MODERN HYDRONICS
continued on pMH22 www.hpacmag.com
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>> Cooling continued from pMH20 STEPS TO CONSIDER Contractors need to fully consider the customers’ expectations. Completely understanding customers’ requirements involves taking detailed notes and leaving specific instructions for the installation department as to the outdoor unit location, drain considerations, type of thermostat required, etc. Contractors should also fully identify all potential problems and advise installers about factors like thermostat location, condensate pump required, plenum changes to fit A-coil, yard access for outdoor unit, etc. Relevant considerations for notes/instructions: • Multiple systems: with hydronic systems, some people want dehumidification more than cooling, which can be satisfied via multiple ductless units in key rooms • Confirm adequate electrical supply before–not during–installation • Determine exact path of drain for condensate from the A-coil, and whether a pump is required (if so, build it into the price otherwise in order to avoid extras or, worse, absorbing the cost) • Remember: there is only one thermostat per system, so instead of simply remounting the new one in the old location, look around to see if there is a better location that would give a better overall comfort level • Building codes require specific amounts of fresh air—find out if fresh air needs to be added to the contract due to negative pressure in the building (and advise the customer, as this will affect the cost) • Access restrictions: never take access for granted—always survey the area before placing equipment in the mechanical room and placing outdoor units on ground or roof • Do not let the customer determine equipment location: the after-the-fact customer will deny choosing the location and blame the contractor for being the expert and not advising. 5. Temporary Spot Coolers are a good solution for an emergency or temporary problem. They were originally designed for urgent cooling requirements for computer rooms or hospitals. They have since developed into a variety of uses including kitchens, living rooms / bedrooms (senior apartments), fixed window rooms, and home offices. One was even spotted in Japan outside the entrance to a major hotel, to keep their customers cool while they lined up waiting for taxis.
High velocity systems are hidden from view except for the diffusers.
3. A PTAC (Package Terminal Unit) heating cooling unit is a low cost alternative. It is a one-piece decorative air conditioner that fits into a room through the wall sleeve. It can be used in existing, renovation, or new construction applications, normally using one unit per room. These units are typically used in hotel and motel complexes, and also commonly found in apartment rentals and condo units. Vast improvements in system technology, energy efficiency, more accurate temperature control and much lower sound levels make this product a viable choice. 4. A high-pressure system is similar to the fan coil system in terms of equipment and offers good dehumidification. This system is easy to install and is primarily placed in the ceiling space or attic of a building using very small diameter plastic pipes with a high velocity fan system. The pipes run to each room from a central location and are hidden from view except for the diffuser. There is very little disruption to the living area and no need to redecorate after the installation. MH22 | autumn 2014
Current Environment Government regulations are getting increasingly tougher with higher and higher energy efficiency goals and third party verification of equipment performance. The end result is more technically advanced products that require better educated and skilled service mechanics. Consumers are more informed and demanding. They want explicit details of what equipment you are supplying and why you chose it. They are Internet savvy and will likely check your information for accuracy before they buy. As a business professional you should always be aware of all current trends to make the best recommendations for each job. You must give your customer all the proper options for their application to keep the competition honest and secure the business. <> - Mike Butler Mike Butler has over 40 years of sales and marketing experience in the HVAC industry with various manufacturers. He is currently with Airon Group of Companies where he is responsible for sales and application solutions.
MODERN HYDRONICS
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The Future of Hydronics is Here Introducing the
Tamas Z-Block The Tamas Zone Block is an all-inclusive, plug-and-play zoning device, capable of pumping to a variety of different applications. The Z-Block is expandable to suit a range of zoning requirements, and can also be used as an injection pump or boiler pump. Ease of installation
Very little soldering needed
Fits into the most awkward of mechanical rooms
Suitable for all skill levels in the trade from first year and up. Custom, Reliable Hydronic Systems Tamas Hydronic Systems Inc. 4516 112 Avenue SE Calgary, Alberta T2C 2K2 www.tamashydronic.com
Expandable up to 10 blocks!
>> Design
Complex Times Call For Basic Measures
I
love how Mother Nature every now and again gives us a good old fashioned smack down, just to remind us who is really boss. The ice storms eastern Canada experienced this past winter are a good example, leaving hundreds of thousands, including yours truly without heat or power. My situation was not as severe as that of many however, having a gas stove we were able to cook and make tea; our standing pilot gas fireplace took the chill off; and our good old fashioned chimney vented standing pilot hot water tank gave us hot showers. The situation definitely illustrated the advantages of older, simpler technology, and made me wish in the moment at least, that I had an old gravity radiator system in my house. Those old standing pilot millivolt boilers could operate without electricity, and the old radiator system could circulate without the aid of pumps simply by relying on the laws of physics, with the heated more buoyant water rising to the top of the system thereby causing the cooler water to return to the boiler creating the natural "gravity" circulation. Now before you go pulling the circulators off your systems let me clarify, I have not become a Luddite and turned my back on technology. I am simply enjoying a moment of nostalgia. Losing power has its benefits and brought neighbours together to help one another out, perhaps rekindling a true sense of community. Many families likely pulled out board games that had been gathering dust for too long and rediscovered the joys of a family game night. I am sure many people have some happy memories of pulling together and coping during this and other blackouts, but I donâ&#x20AC;&#x2122;t see many MH24 | autumn 2014
cancelling the utilities and making it a permanent lifestyle choice. Having an old technology boiler system that will still work when the power goes out is definitely desirable, but paying the higher utility bills that go along with it may not be. Unfortunately I see far too many under performing systems out there, and usually not because the technology is lacking, but because it is improperly installed, misapplied, not understood and/or under utilized. In order to understand what I mean, letâ&#x20AC;&#x2122;s look at some of the most common errors we see and how they negatively affect efficiency: oversizing, short cycling, over pumping and improper piping strategies. Oversizing of boilers continues to be an issue in our industry, and in the case of a boiler, bigger is not better. Burner modulation, which is a feature on over 90 per cent of the boilers I sell these days, certainly helps but it does not solve this problem altogether. If a boiler could modulate infinitely, firing once at the beginning of the heating season and never turning off until the spring, this would approach optimal efficiency. Multiple boiler plants, operating and modulating together can most closely approximate this, but even so we must be careful not to oversize. I understand nobody wants to be caught short but in truth I have been in this business for almost 35 years and I can count on one hand the number of jobs I have seen where the boiler plant was undersized. An accurate heat loss and properly sized boiler plant is the first step to a truly efficient hydronic system. The second most common problem I see is directly related
MODERN HYDRONICS
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Modern Hydronics
to boiler over sizing and it is boiler short cycling. When a boiler, or boiler plant is too big it produces heat faster than the system can deliver it to the building, which causes the boiler to overheat and shut down until the system catches up, repeating this on/off cycling over and over again. Not only is this detrimental to efficiency, much like stop and start city driving in a car, but it also results in more wear and tear on many of the components. Short cycling is a far bigger issue than most people realize and has a dramatic impact on efficiency. I had my eyes opened to just how much several years ago on a commercial retrofit project I was involved in. We had worked with the same company on several buildings, achieving on average gas savings over 35 per cent, but we were only seeing savings of about 10 per cent in one building. After many hours of monitoring and lots of pulling my hair out, we finally discovered a defective relay in one boiler which had resulted in that boiler continually cycling on and off. Once this relay was fixed and the short cycling issue corrected, the savings jumped up more than 20 per cent. Short cycling is a problem that needs to be addressed and it is not simply a matter of proper sizing. Oversized pumps can also contribute, which leads me to my next point. Just as we like to over size boilers, we seem to have the same penchant for over sizing pumps. As with boilers, when it comes to pumps bigger is not better. While the boiler produces the btus required to heat a building, the pump is the device that moves these btus to where we want them to go. The universal heating equation (GPM = BTUH ÷ ΔT x 500) shows how this works; GPM is the gallons per minute flow rate the system requires at a given point in time. BTUH is the heating load at a given point in time, Delta-T (ΔT) is the designed-for temperature drop of the fluid; and 500 is a constant representing 100 per cent water. When we oversize a pump and deliver more GPM, our delta T is proportionally reduced. How does this affect efficiency? It can result in overheating , short cycling, less than optimal comfort and poor performance. I am sure many of you have been in boiler rooms and seen the boiler inlet temperature only three or four degrees cooler than the supply temperature, this is a sure sign of over pumping. Properly sized pumps need to work with the boiler to deliver the heat at the rate required and designed for, ideally we should be using the variable frequency drive (VFD) pumps that are available to optimize this and work in tandem with the modulating boilers. If we are modulating the firing rate of the boiler then does it not make sense to also modulate the flow rate to match the demand? As you may have noticed, all of these things are related and one leads to the other. The goal is to match the size of the www.hpacmag.com
boiler plant to the actual demand of the project. Secondly, we need to deliver the correct amount of heat to the system components with properly sized pumps. The properly sized boilers and pumps can only do their jobs well if the piping is sized and installed correctly also. Sadly, I could fill this entire magazine with stories and examples of the piping nightmares I have seen. Following a piping diagram is a good start, but there really is no substitute for a good fundamental understanding of how and why it works. If you are installing systems you really need to take the time to understand the whys. I hate to say it, but far too many of the poor underperforming jobs I see on a regular basis are the result of poor or improper piping. I know this sounds harsh but unfortunately it is all too often the sad truth. As a wholesaler I would love to be able to say “Here you go, just buy the boilers we sell and your installs will be problem free and save your customer 30 to 40 per cent on their bills.” Do we sell problem free systems? Absolutely. Can properly sized and installed hydronic systems save upwards of 30 and 40 per cent fuel usage? Yes they can, I have seen savings over 50 per cent on rare occasions. Is it simply a matter of choosing the “right” brand? Absolutely not. The truth is every manufacturer and every wholesaler today offers high efficient, high quality equipment that is capable of doing the job. What is the magic bullet? Good old fashioned knowledge. We really do need to read those installation and operation manuals nowadays. Even better, take advantage of the many training opportunities that are offered by manufacturers and wholesalers as well as trade organizations. The more education and knowledge you get, the better systems you can install and set yourself apart from the pack. Designing and installing an efficient and reliable hydronic heating system is not simply a matter of picking all the right pieces and including all the latest and greatest controls, components and gadgets. Take the time to understand the fundamentals – the how and the why of things will never be out of date. <> - steve goldie
MODERN HYDRONICS
Steve Goldie is with NEXT Plumbing Hydronics where he is the hydronics specialist. He learned his trade from his father while working as a plumber in the family business. He joined the wholesale side of the business in 2002 after 21 years in the field. Steve is frequently called on to troubleshoot systems and advise contractors. He can be reached at sgoldie@nextsupply.ca. autumn 2014
| MH25
>> System Design
Less Is More Get the flow you want, where and when you want it.
M
ost hydronic system designers have their preferred way of doing things. Sometimes this is based on comfort level, sometimes it is based on experience, and other times it may be out of habit. What follows is a description of a design option described by ASHRAE as “a series circuit with compound pumping.”* This approach is worth a look for a number of reasons: it uses less raw material; can reduce installation time and maintenance costs; and may improve system operating efficiency thereby increasing the longevity of the system. Unlike other systems, this design option uses pumps for zoning as opposed to zone valves. Flow can be directed straight at the terminal unit with the necessary flow for it, rather than manipulating pressure points in the system that would force flow through a terminal unit.
no limit to the number of loads that come off, as the primary loop size is determined based on total Btuh load and the anticipated deltaT and flow rate needed. This method can be used for heating and/or cooling distribution systems (see Figure 1 for cooling). In larger systems, it may make sense to split the system into two smaller loops (as shown in Figure 2). Balancing may be needed for each loop in this case. Figure 3 shows the piping arrangement between the primary loop and the terminal unit. By taking care of the flow through each terminal unit with a dedicated small wet rotor circulator, and by keeping the restriction/pressure drop through the primary loop to a bare minimum, the primary pump can often be much smaller since continued on pMH28 Figure 2 Two loop primary with loads
WHAT IT LOOKS LIKE The system consists of a single pipe distribution loop with loads hydraulically decoupled through a primary/secondary arrangement (closely-spaced tees), or a manufactured twin tee. Wet rotor circulators match the specific flow needed to each of the terminal units or heat emitters. Most heat emitters or loads referenced here are fan coils. This design works really well for applications where several loads are located throughout a building. Instead of running two large Supply and Return lines in parallel, simply run a single pipe loop through the building and draw loads off the primary loop where needed. There really is
Figure 1 Single loop primary with loads Figure 3 Piping example of terminal unit
* 2008 ASHRAE Handbook – HVAC Systems and Equipment, p12.2 MH26 |
autumn 2014
MODERN HYDRONICS
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The Evolution of High Efficiency Condensing Boilers High efficiency stainless steel boiler Models from 46,000 to 151,000 BTU/Hr Available in a combi version Fully modulating with 5:1 turndown Advanced outdoor reset control Venting to 150' 2" venting on all models up to 100'
Tx
>> System Design continued from pMH26 â&#x20AC;&#x153;A larger primary loop delta T often creates better source efficiencies.â&#x20AC;? it does not need to overcome the head of the entire system. The primary pump may then be controlled based on a deltaT across the primary loop that will become a function of system load, rather than running full speed at all times. A larger primary loop deltaT often creates better source efficiencies, for example, when using condensing boilers by managing loads in the system achieved by cascading the terminal units. Figure 4 Piping sketch for heating and cooling
The individual load wet rotor circulator is a standard off-theshelf component. Only those attached to terminal units that are calling are being operated. Significant energy savings can be realized by this strategy throughout the life cycle of the system. Heating and cooling In systems with four-pipe terminal units, used for heating and cooling, the design can easily be duplicated for either scenario as shown in Figure 4. Here, the heating loop and the cooling loop each have their own primary loop and load setup, allowing for simultaneous heating and cooling in different parts of a building. Alternatively, if the terminal units are two pipe only, then a diverting valve could be used to pull off the heating or the cooling loop depending on load requirement. TEMPERATURE MANAGEMENT As additional loads are taken off the primary loop, the terminal units downstream are being supplied with a changed water temperature, which can be calculated as shown in continued on pMH30
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Thermo 2000 Inc. 500, 9th Avenue, Richmond,Canada, JOB 2HO www.thermo2000.com MODERN HYDRONICS
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Think Competitively. Think Thermal Sub-metering. The innovation, best practices and benefits behind the sub-metering of central hydronic heating and cooling systems in new condominium construction is now being widely recognized and adopted. Installation within the fan coil or heat pump units means energy savings with no impact on valuable suite floor space. Adding thermal to electricity and water sub-metering will accelerate unit sales given the increased market appeal of lower maintenance fees and enhanced unit owner control of utility costs.
Think EnerCare. EnerCare Connections is the largest non-utility sub-metering provider in Canada and at the forefront of thermal metering solutions in Ontario. We understand all the challenges – yours, the developer’s and the unit owner’s. That’s why we offer on-time, cost-effective, turn-key multi-utility solutions that require no upfront capital costs and come with attractive installation allowances. Think about how thermal sub-metering, as part of a full-utility metering solution, will give your project that innovative, competitive edge you are looking for.
Contact us at 416-649-1890 or visit EnerCare.ca/thermal-sub-metering
>> System Design continued from pMH28 Figure 7 Vertical Piping Example
Figure 5 Mixed water temperature calculation
circulators to go with them. Some design software exists today that will handle the pipe sizing and flow calculations automatically, and also that of the temperature rise in between the terminals in such systems.
Figure 6 Horizontal piping example
HORIZONTAL DISTRIBUTION In order to minimize the amount of piping that goes into a project, a very efficient approach for low rise buildings is to have a supply riser on one side of the building and a return riser on the other side of the building. The primary loop for each floor is then run in between those two risers. The loads come off in between as shown in Figure 6. VERTICAL DISTRIBUTION There really are no height limitations with this system. For high rise applications, a supply loop is routed to the top of the building and the return loop is near the bottom floor. Individual distribution risers fed vertically through the building pick up the terminal units along the way, floor by floor as shown in Figure 7. Consider this design approach on one of your next projects. With up to 40 per cent less pipe and fewer parts, as well as significant labour savings, this may be another option for you to differentiate yourself from that of your competitors while still achieving energy savings and improving system efficiency. <>
Figure 5. Depending on the primary flow, flow and deltaT through each terminal unit, the temperature drop will be determined. It is important to calculate those temperature changes prior to selecting the terminal unit or the wet rotor MH30 | autumn 2014
MODERN HYDRONICS
Mike Miller is director of commercial sales, Canada with Taco Canada Ltd. and chair of the Canadian Hydronics Council (CHC). He can be reached at hydronicsmike@taco-hvac.com. www.hpacmag.com
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