GREEN HEAT A self-sustainable envelope heating system using in-pipe micro-hydro electric power system Darpan Pradeepkumar Arora ARC 5423 - Ecological Issues | Spring 2017 | Final Project Professor Shannon Schmehl
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With current trends of energy consumption, it would be difficult to change user habits at a global scale against the rate of use of non-renewable resources to generate power. Hence, clean energy generation as well as reduction in external energy consumption is what GREEN HEAT addresses. This proposal looks at the possibility of generating electricity from pressurized water that is used in hydronic heating system for commercial space heating purposes. It is an investigation into the possibility of generating power through micro-hydro turbines to generate power and using it to heat up convector plates or a coil for building envelope heating. Generating hydroelectric energy through turbines is not new concept. But despite of continuous water flow through our pipe distribution systems in buildings, there seems a limitation in harnessing that mechanical energy into electrical energy of certain use. Through my initial research on the topic I found that a company in Portland, Oregon called Lucid Energy has recently developed and installed turbines in the city’s water supply pipe system to harness energy resulting from excess water pressure. What if that concept can be mimicked at a micro-scale for heating purposes? Is it possible to significantly cut down on energy consumption required for space heating in buildings? This project addresses these questions and proposes a concept merging the principles of micro-hydro power generation and induction heating.
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1.
Abstract
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Energy use in construction industry …………………
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Hydroelectricity through water pipes a. b. c. d.
………. Case study 1: LucidPipeTM Power System ……… Case study 2: Leviathan Energy’s BenkatinaTM …… Understanding hydronic heating system ……… Understanding micro-hydro power system
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Principles of induction heating
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GREEN HEAT System a. The Concept ……………………........................ 16 b. Energy calculations …………………………..... 19 c. Target audience ………………………………………... 21
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End notes ……………………………………………………. 22
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According the U.S. Green Building Council (USGBC) Americans spend almost 90% on their time indoors. The construction industry is one of the largest consumers of the two dominant energy sources in the world – electricity and natural gas, which are non-renewable resources. According to the U.S. Energy Information Administration (EIA) results from the Commercial Building Energy Consumption Survey (CBECS) in 2012 show that electricity and natural gas usage increased by 19% and 7%, respectively, since 2003 (figure 1) whereas, the total energy usage in commercial buildings has increased 7%. We still rely on electricity and natural gas for 93% of our energy demands. (figure 2) Today, slowly but increasingly, there is a shift towards clean energy generation in the world. However, our rate of consumption of nonrenewable resources is much higher than the rate of replenishment. In 2015, about 40% of total U.S. energy consumption was consumed in residential and commercial buildings, the EIA states.
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Figure 1: Total energy consumption in commercial buildings in the U.S. as tracked by CBECS.
Figure 2: Shares of major energy sources in commercial buildings in U.S., 2012.
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Narrowing down that energy consumption by their end use, space heating in commercial buildings in the U.S. accounts for 25% of the total energy consumption (figure 3), the EIA states. However, on the contrary, CBECS 2012 survey states that a slower growth in commercial building energy demand since 2003 is explained by newer construction that is built to higher energy performance standards. Building envelopes are one them, which in fact determine energy demand for interior spaces.
Figure 3: Energy use in U.S. commercial buildings by major end uses, 2012.
Majority of buildings use hydronic heating, which requires heating water in a boiler and circulating it throughout a building’s perimeter for envelope heating. According to a report by Ernesto Orlando Lawrence Berkeley National Laboratory, water heating accounts for approximately 15% to 35% of the total commercial building fuel usage. How can we significantly reduce this energy consumption? How can an efficient envelope heating system be sustainable? GREEN HEAT addresses these questions and provides customized sustainable solutions.
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Fossil fuels supply about 80% of global energy use and the demand is growing close to 2% per year. As non-renewable resources, their use is clearly unsustainable - The Sustainable Scale Project
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The use of falling water has long been a source of energy, converting the potential energy of a water source into electrical energy. The basic principle of hydropower is that if a water can be piped from a higher level to a lower level, the resulting water pressure can be used to do work. This has been long used in dams, however, at a much larger scale with a capacity of more than 1000 Kilowatt of power output. Then there are Small scale hydropower systems in the range of 500 to 1000 Kilowatt power output and Mini hydropower systems with a capacity between 100 to 500 Kilowatts. Hydropower installations with a power output of less than 100 kilowatt (or less then 1000 Watt) are micro-hydro power systems. What are the system components? Micro-hydro power systems basically comprise of five components, that determine the final power output. 1.
WATER INTAKE SOURCE: The more amount of water stored at the source, the more potential energy it provides.
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Figure 4: Illustration showing components of a typical high head hydro installation at a regional scale.
Water source Hydraulic head Penstock pipe system
Figure 5: A generic illustration of micro-hydro system components.
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2. HYDRAULIC HEAD: The vertical
difference in level of the water flow from the source to the turbine is its head. The more head available, the energy it can generate. (figure 5)
3.
TURBINE: A turbine converts the excess pressure of water into rotating shaft power. (figure 6) Broadly categorized, by their principle way of operating, into impulse and reaction type of turbines; they can be classified into high head, medium head, and low head machines.
4. GENERATOR: An assembly of
Generator
Turbine
Figure 6: An example of in-pipe water turbine connected to a generator outside the pipe.
rotating coils in a magnetic field which induces current. This flow of current for a particular amount of time generates power.
5.
PENSTOCK PIPE SYSTEM: An enclosed pipe that delivers the water to a hydro turbine is called a penstock. (figure 5)
GREEN HEAT uses a penstock pipe system in the building, with available high head, to deliver pressurized water to a Fuji micro-tubular water turbine to generate power.
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Figure 7: Diagram of Lucid Energy’s pipe system installed in Portland, Oregon.
Lucid Energy became the first company in the U.S. to install a commercial micro-hydro energy system in Portland city’s water supply system. The 200 kW system harvests excess pressure from the gravity flow of water inside the Portland Water Bureau pipeline. How does it work? Four 42” spherical turbines (figure 7) spin as fast-moving water flows through them, generating an average of 900 megawatt hours of electricity per year – enough to power approximately 100 homes and help the city meet its Climate Action Plan goals. The system extracts approximately 20psi of pressure from the pipeline and converts it into electricity to supply it to the grid – with no impact on water delivery. ARC 5423 Ecological Issues | Spring 2017
Figure 8: Installation of LucidPipeTM system inside Portland Water Bureau’s pipeline.
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Figure 9: Power output and flow requirements as provided by Lucid Energy.
What are the system benefits? • CLEAN ENERGY: uses gravity fed water to turn the potential energy of water into renewable power. • REDUCES VALVE WEAR: reduces
excess water pressure in pipeline.
• RELIABLE:
provided >95% of efficiency in the first eight months of operation. Sensors in the turbine track for chemicals and impurities in the water.
• FEASIBLE: fits different pipe sizes
according to the source or existing system. (figure 9)
This case study provides valuable information on practical applications of micro-hydro power system and the workability of in-pipe turbines, which can be scaled accordingly. ARC 5423 Ecological Issues | Spring 2017
Figure 10: Technological detail of a single microhydro turbine as designed by Lucid Energy.
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Benkatina™ is an in-pipe turbine which converts water flow and pressure into electricity, maintaining downstream pressure and achieving high efficiency even with variable flows. This system is perfect for scaling down a micro-hydro electric system at building application level as it can be adapted to various pipe sizes and configurations. This system includes: a turbine, a generator, and optional customized sensors and electronic sub-elements as provided by the company.
Figure 11: Illustration of Leviathan Energy’s BenkatinaTM in-pipe hydroelectric system.
Quick facts about the current Benkatina™ model: 1. Unit size: Approximately 100cm W x 110cm L x 106cm H 2. Customized power capacity: Currently up to 10 Kilowatts 3. Output voltage: Suitable for configurations up to 500 volts (including 12V, 24V, 48V batteries) 4. Flow range: Varies according to project (one example is 36 m3/hr to 72 m3/hr) 5. Pressure/ head range: Usually 10 to 80 meters (1-8 bars) What are the system benefits? • INSTALLATION: provides easy and quick installation with immediate benefits. • MAINTAINANCE: as it is handy, it is easy to maintain or replace quickly. • AFFORDABLE and DURABLE: provides a return on investment of 20%-30% per year. • FEASIBLE: suits best for building scale and for various pipe sizes, water flow and head. ARC 5423 Ecological Issues | Spring 2017
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For any building application, the power output from the turbine depends on:
Head (m)
Flow (m3/hour)
Head (m)
Flow (m3/hour)
The rate of flow of water through the cross-section of the pipe.
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300-800
10
350-800
10
150-400
20
150-400
2. The available head, i.e. the gross
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75-200
40
75-200
30
50-400
60
50-150
40
40-100
1.
vertical distance of downstream flow of water from its source.
The more the flow and head available, the more energy is produced. This energy can be harvested as on-grid or off-grid applications. On-grid use includes injecting excess power to the grid for sufficient return on investment. Offgrid applications include for example- charging of batteries that can be used for powering lighting and sensors at any water station.
Figure 12: According to BenkatinaTM Left: Head and flow requirement to produce 5-10 Kilowatt of power Right: Head and flow requirement to produce 10-20 Kilowatt of power
This proposal targets off-grid application of this in-pipe hydroelectric system, however, in a commercial building. GREEN HEAT micro-hydro uses BenkatinaTM electric system to convert its power output directly into heat for building envelope heating. It uses a 4� pipe system in a commercial building, however, the head and flow of the building determines its efficiency. ARC 5423 Ecological Issues | Spring 2017
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One of the oldest heating systems used across North America is hydronic system which uses heated water as a medium to transfer heat to interior spaces of a building, including the building envelop. Water has a higher heat holding capacity than air. The heat is absorbed by the water at the source such as a boiler, moved through the distribution piping by the water and released to the spaces via a heat emitter – a radiator, a convector or a baseboard. 1.
Figure 13: Layout of a typical hydronic heating system.
RADIATOR: is usually cast-iron, tall and bulky unit that can stand on feet or hang on walls. It has more heating capacity per length that convectors and baseboards.
2. CONVECTOR: is usually cast-iron
enclosed in a sheet metal cabinet with opening at top and bottom for air to flow through. It is slow, but consistent, in radiating heat.
3.
BASEBOARD: can be heating by electricity, hot water or steam. It has a low profile and can be steel, cast-iron, copper or aluminium.
Figure 14 : A convector heater used for envelope heating near a building’s entrance.
GREEN HEAT provides sustainable heating solution eradicating the need to heat up the water at all. ARC 5423 Ecological Issues | Spring 2017
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Some materials are good conductors of electricity, some are poor. Poor conductors offer resistance when a current flows through them. They work by converting that electrical energy to heat energy. Even a thin coil of wire, called filament, will heat up when current flows through it. This property of some metals make them good heating elements. What is a heating element? It is a sturdy electrical component designed to dissipate heat when connected to a power supply. A typical heating element is a coil, a ribbon (straight or corrugated), or a strip of wire that gives off heat to warm the ambient air around it. Heating elements are typically nickel-based or iron-based. GREEN HEAT uses nichrome coils (80% nickel, 20% chromium) in its convector units as they have high resistance and low expandability. ARC 5423 Ecological Issues | Spring 2017
Figure 15 : Left: A heating coil connected to a power source. Right: Corrugated ribbon heating element.
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SAFETY GRILL
4” HDPE PIPE
NICHROME COIL
METAL CASING WATER FLOW
Figure 16: Illustration of the GREEN HEAT convector unit.
Hydronic heating is one of the most efficient ways used in commercial buildings in the U.S. for building envelope heating purposes. However, as mentioned earlier, space heating uses 25% of total energy consumed by commercial buildings and 15 – 30% of that energy goes into heating water. GREEN HEAT provides a selfsustainable envelope heating system that heats up nichrome coil in its convector (figure 16) from the power provided by BenkatinaTM ‘s micro-hydro turbine system. ARC 5423 Ecological Issues | Spring 2017
Figure 17: Turbine system connected to generate power. Final Project
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How is it sustainable? While conventional hydronic heating systems rely on a heat source (generally a boiler in the basement), GREEN HEAT systems do not need heating water all together. This is where the 25% energy – generally used in water heating – is saved. How does it work? This system promotes the use of clean energy generation by merging the principles of micro-hydro electric generation and induction heating. 1. It utilizes the available building height (i.e. the hydraulic head) to force water by gravity through a micro-hydro turbine that rotate a shaft to generate electricity. 2. This electricity is passed through a high resistance nichrome coil which heats up in response the flowing current. 3. When ambient air passes through the convector unit (figure 18) it rises in temperature heating up spaces around it. 4. The water is then re-circulated by a pump to the high head water intake source. (figure 19) 5. A heat sensor connected to the coils cuts off the circuit in case of excess heating. ARC 5423 Ecological Issues | Spring 2017
Figure 18 : Concept development sketches. Above: Conventional hydronic convector (plan & section) Below: Proposed convector system (plan & section)
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What are the system advantages? GREEN HEAT has partnered with Leviathan Energy’s BenkatinaTM hydroelectric system to provide the end users a care-free envelope heating – running on green power. Following are the benefits these systems provide: 1.
SUSTAINABLE: Though turbine’s efficiency is 75% (considering energy losses) compared to 90% of conventional system, Green Heat completely eradicates the need for heating water – saving commercial building energy consumption significantly.
2. COST EFFECTIVE: These systems
run at minimum energy intake and have a return on investment of 2 to 4 years and totally eliminating the need for a boiler.
3.
ADAPTABLE: Recommended for buildings with high head, these systems can also be fitted to low head buildings having water pumped to achieve a high flow.
Figure 19 : Typical layout of a Conventional hydronic system vs proposed GREEN HEAT system.
4. FEASIBLE: These systems require
minimum maintenance as pipes are at room temperature.
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Let us take an example of a building with the following considerations to base the calculations on: 1. Physical factors: a. Minimum available head= 30 m (differential head= downstream-upstream flow) b. Pipe diameter= 4” HDPE pipe (ignoring friction in the pipes) 2. Operational factors: 1. Water flow= 3000 liters/ minute (gravity or pump fed) 2. Time period= as required.
HYDROPOWER OUTPUT: An example provided by BenkatinaTM for a building having 30m differential head with a flow of about 3000 liters/ minute should yield a power output about 9.6 KW per hour. Hence, considering the theoretical equation and the considerations provided by BenkatinaTM : H= 30m, Q= 0.05 m3/s, density of water= 1000 kg/m3, g= 9.81 m/s2
The theoretical power (P) available from a given head of water is in exact proportion to the head H and the flow Q. P= Q × H × c [where, the constant ‘c’ is the product of the density of water and the acceleration due to gravity]
P= 0.05 * 30 * 1000 * 9.8 P= 14.715 KW As the turbine always has an efficiency lower than 1, considering a reduced efficiency of 65%, power P= 14.715 * 0.65 P= 9.56 KW ARC 5423 Ecological Issues | Spring 2017
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POWER TO HEAT CONVERSION: For any heating element, rise in its temperature is measured in energy change for certain amount of time. Hence, there is a need to convert power into energy and then to heat.
Specific heat capacity (C) of Nichrome-60 (80% Ni – 20% Cr) = 460.58 J/Kg-K or 0.11 BTU/ lb-°F
Let us consider a nichrome coil at room temperature, say 70 °F, and we want to heat it up to 120 °F. The amount of energy available per hour is 32780 BTU. (see right)
A power of 9.6 KW per hour would generate an energy of 32780 BTU per hour. - Energy and Power Conversion Calculator,
chuck-wright .com
Now, the amount of heat needed to heat a subject from one temperature level to another can be expressed as: Q = C m ΔT where, Q is total energy, C is the specific heat capacity of nichrome, ΔT is the change in temperature. 32780 = 0.11 * m * 50 °F m = 32780 / 5.5 m = 5960 lbs Hence, with available energy from micro-hydro power, 5960 lbs of coil can be heated by 50 °F for 1 hour. (not considering energy losses). The increase in temperature requirement can be adjusted against the density of nichrome type used. ARC 5423 Ecological Issues | Spring 2017
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GREEN HEAT is practically suitable for any building type provided it has the required head and water flow (gravity or pump fed) to generate sufficient electricity to heat up coils for convection heating. Preferably, high rise buildings or buildings running 24x7 are best suited for these systems again considering feasibility of the proposal – i.e. the life cycle costing of the system. Some examples of those building types include: 1. High rise commercial offices 2. Healthcare facilities 3. High rise or Mid-rise residential buildings 4. Industrial facilities running using a lot of water. GREEN HEAT also provides state-ofthe-art customized solutions (as best suited) for envelope heating in lowhead buildings. Reach out for more information.
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i.
Cover page Graphics: Hydropower, SOAR Hydropower. Retrieved April 26, 2017, https://soarhydro.com/
ii.
Figure 1: U.S. Energy Information Administration - EIA - Independent Statistics and Analysis. Retrieved April 24, 2017, https://www.eia.gov/consumption/commercial/reports/2012/energyusage/
iii.
Figure 2: Energy Use in Commercial Buildings. Retrieved April 25, 2017, http://www.eia.gov/energyexplained/index.cfm/data/index.cfm?page=us_energy_commercial
iv.
Figure 3: Ibid.
v.
Figure 4: Klunne, Wim Jonker. Introduction to hydropower. Retrieved April 29, 2017, http://www.microhydropower.net/basics/intro.php
vi.
Figure 6: Seth, Radhika. (2011, March 06). Hose Without the Guilt. Retrieved April 29, 2017, http://www.yankodesign.com/2011/03/04/hose-without-the-guilt/
vii.
Figure 7: Lucid Energy. How it Works. Retrieved April 29, 2017, http://lucidenergy.com/how-it-works/
viii.
Figure 8: Ibid.
ix.
Figure 9: Ibid.
x.
Figure 10: Ibid.
xi.
Figure 11: Leviathan Energy. Power from your pipes. Retrieved April 29, 2017, http://benkatina.com/index.php?option=com_content&view=article&id=8&Itemid=120
xii.
Figure 12: Ibid.
xiii.
Figure 13: P.L. Marketing. Hydronic Heating Systems - Ottawa, Toronto. Retrieved April 29, 2017, http://plmarketing.ca/furnaces-and-heating/hydronic-heating-systems/
xiv.
Figure 14: Sterling Heat. Retrieved April 30, 2017, http://www.sterlingheat.com/#
xv.
Figure 15: How do heating elements work? (2016, March 01). Retrieved April 30, 2017, http://www.explainthatstuff.com/heating-elements.html
xvi.
Calculations done with the help from: • Hydropower. Retrieved April 30, 2017, http://www.engineeringtoolbox.com/hydropower-d_1359.html • What's a Watt?. Retrieved May 01, 2017, http://chuck-wright.com/calculators/watts.html
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For more information, contact: Darpan Arora LEED Green Associate darora@ltu.edu | (248) 600-3686
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GREEN HEAT Envelope Heating Solutions