Energy Modeling Report - Office Renovation by ENlight Design LLC

Energy Modeling Report Provided to: (taken out for confidentiality purposes) 9.22.2010 Report Written by: Jacob Dunn Submitted by:

Table of Contents Project Parameters …………………………………………………………………...............................

Introduction …………………………………………………………………………………………………

Section 1 - Energy Efficient Building Tax Deduction Section 1.1 - Intent ……………………………………………………………………………..

Section 1.2 - Whole Building Cost Analysis Method Certification Documentation ………

4-6

Section 1.3 - Interim Lighting Rule Certification Documentation …………………………..

6-7

Section 1.4 - Additional Certification Requirements …………………………………………

7-8

Section 2 - Reap Grant Section 2.1 - Introduction ……………………………………………………………………….... Section 2.2. - Energy Modeling Methodology ……………………………………………….

9-17

18-22 Section 2.3. - Energy Savings …………………………………………………………………… Section 2.4 – Conclusion …………………………………………………………………….

Disclaimer While the recommendations in this report have been reviewed for technical accuracy and are believed to be reasonably accurate, the findings are estimates and actual results may vary. As a result, ENlight Design LLC is not liable if projected estimated savings or economics are not actually achieved. All savings and cost estimates in the report are for informational purposes, and are not to be construed as design documents or as guarantees. The owner shall independently evaluate any advice or direction provided in this report. In no event will ENlight Design LLC be liable for the failure of the customer to achieve a specified amount of energy savings, the operation of customer’s facilities, or any incidental or consequential damages of any kind in connection with this report or the installation of recommended measures. 2

Project Parameters Project Description – A small, approximately 1958 square foot office renovation in Moscow, Idaho Owner – (taken out for confidentiality purposes) Design Team – (taken out for confidentiality purposes) Contractor – (taken out for confidentiality purposes) Energy and Lighting Consultants – ENlight Design LLC

Introduction This document analyzes various energy efficiency measures designed by the architect for an office renovation project by means of building simulation modeling. Energy Plus Version 5.0 was principally used to quantify the energy savings from multiple passive and active strategies proposed by the architect. This report is intended for two purposes and is divided into two separate sections. The first section contains the information and submittal requirements for the Energy Efficient Commercial Building Tax Deduction (CBTD), while the second section documents the information necessary for pursuing Rural Energy for America Program (REA) grant funding for the project.

Section 1 – Energy Efficient Commercial Building Tax Deduction Section 1.1 – Intent This section of the report is intended to provide the documentation necessary to attain building certification for the Energy Efficient Commercial Buildings Tax Deduction (CBTD) created by the Energy Policy Act of 2005. The documentation will present the certification information required to achieve tax deduction bonuses applied to electrical lighting savings, which can take the form of two different certification paths. The “whole building cost method” includes proving through energy modeling that the building’s upgraded lighting systems will save at least 16 2/3% of the total annual energy and power costs when compared to a reference building meeting the minimum requirements of ASHRAE standard 90.1 2001. This report will show that the proposed building saves the required amount of energy and power savings for lighting energy, but not for total energy consumption. The second “interim lighting rule” pathway requires that the lighting power density for the spaces receiving energy efficiency lighting measures is between 25-40% less than the values calculated by the ASHRAE 90.1 2001 space-by-space method. This document provides documentation and verification that the proposed lighting upgrades will meet the requirements of at least one certification pathway. The application for the tax deduction requires having a licensed engineer in the jurisdiction of the project fill out and submit a designated certification of compliance letter to the IRS. Given that ENlight Design LLC is not a licensed engineering firm, the information provided in this report is intended to be used by a licensed engineer meeting the description above to fill out the required certification documents. A detailed description of this process has been provided by the National Electrical Manufactures Association (NEMA) and can be found here: http://www.efficientbuildings.org/PDFs/GuidanceonEPACTTax-Incentive-Certification-Letters-rev607.pdf.

Section 1.2 – Whole Building Cost Method Certification Documentation The requirement for this certification pathway includes showing a 16 2/3% savings in overall energy consumption and power costs over the reference building with energy efficiency lighting upgrades. The design measures for this report include multiple upgrades from the ASHRAE standard 90.1 2001 standard in both the quantity and quality of light. The reference standard requires a lighting power density of 1.3 watts per square foot for enclosed office spaces without requiring any type of photocontrol system or occupancy sensors. The new design incorporates a much lower lighting power density of .7 watts per square foot (refer to section 1.3 for detailed verification), and utilizes a three-step switch dimming photocontrol system to reduce lighting energy consumption even further. Two daylight sensors are used for each zone and are placed in the middle of each space, 32 inches off the ground with a 250 lux 100% threshold. Figure 1.2.1 displays the amount of lighting energy savings from this energy efficiency measure. [Figure 1.2.1 Total Lighting Energy Savings] 12,000

10,000

8,000

Kwh

68% 6,000

Savings Interior Lighting

4,000

2,000

‐

ASHRAE2001_Baseline

in Kwh Lighting Energy

Upgraded_Lighting

ASHRAE2001_Baseline (1.3 W/sqft) 11,175

Upgraded_Lighting (0.7 W/sqft) with Daylight Sensors 3,600

Savings in Energy

7,575

% Energy Savings

68%

The figure above shows that the lighting upgrade saved a total of 68% of lighting energy savings and consequently 68% of lighting power cost. Figure 1.2.2 translates this decrease in lighting consumption into total energy savings and cost savings.

[Figure 1.2.1 Total Energy and Cost Savings] 300,000

‐4.7%

250,000

200,000 Heating

KBTU

Cooling Fans

150,000

Interior Lighting Exterior Lighting Interior Equipment 100,000

Water Systems

50,000

‐

ASHRAE2001_Baseline

in KBTU Heating

Upgraded_Lighting

ASHRAE2001_Baseline

Upgraded_Lighting

146,769

Heating Savings(%) Cooling

-30.9% 6,474

4,341

38,131

32.9% 12,284

Cooling Savings(%) Interior Lighting

192,075

68%

Lighting Savings(%) 9,554

9,554

Interior Equipment

21,999

Fans

16,103

11,601

Exterior Lighting

Water Systems Total(KBTU) Total Savings(KBTU) Total Savings(%)

32,605

271,635

284,459 (12,824.0) -4.7%

The total energy consumption is shown to increase by 4.7%. The heating energy increased by 30%, the cooling energy decreased by 32.9%, and 68% of the lighting energy is saved. The total energy savings figure is skewed by the fact that by turning off the electrical lighting in the building increased the overall heating energy, especially given the old 2001 code standard’s inflated lighting power density of 1.3 watts/sqft. Typically, the decrease in electrical lighting energy and cooling energy would offset this penalty and lead to a net benefit of energy intensity. However, in the case of Moscow’s heatingdominated climate and the program’s other low internal loads, turning off so many lights with a high 1.3 watt per square foot lighting power density lead to a large penalty in heating with a savings on only a relatively small amount of energy attributed to cooling. The energy efficiency upgrade still does, however,

save on the overall cost because of the utility price difference between kilowatt hours used for cooling and lighting versus therms used for the gas heating coils of the baseline system. Figure 1.2.2 shows a breakdown of the end use energy consumption by fuel type, the utility rate for the property, and cost calculations. [Figure 1.2.2 Total Cost Savings by Fuel Type] Upgraded_Lighting (0.7 W/sqft) with Daylight Sensors

ASHRAE2001_Baseline (1.3 W/sqft) 1,468

Heating(Therms) Cents/therm Heating Cost($)

1,921

88 $

1,288.94 $

1,686.82

Cooling(Kwh)

1,897

1,272

Lighting(Kwh)

11,175

3,600

Other(Kwh)

23,523

22,204

Total Kwh

36,596

27,076

Cents/Kwh Eeletricity Cost($) Total Cost ($)

3,659.59 $

2,707.61

4,948.53 $

4,394.43

Total Cost Savings($) % Cost Savings

554.09 11.20%

Overall, the project incurred a 4.7% increase in overall energy usage, but saved a total of 11.2% on the power cost, which doesnâ&#x20AC;&#x2122;t qualify the building for CBTDâ&#x20AC;&#x2122;s 16 2/3% reduction requirement. However if you look at the fact that the building saves 68% of the lighting energy and power costs, it may still have a chance for certification, depending on the language of the requirements. Figure 1.2.3 shows some images from the Radiance daylighting model that informed the energy model. [Figure 1.2.3 Daylighting Simulation Renderings

Section 1.3 – Interim Lighting Rule Certification Documentation This certification requirement looks to document a project’s decrease in lighting power density after efficiency measures in the range of 25-40% savings over the ASHRAE standard 90.1. For office spaces, the baseline reference lighting power density is 1.3 watts per square foot for office spaces and 1.0 watts per square foot for other utility spaces. Figure 1.3.1 shows a breakdown of the lighting fixtures and their constituent wattage outputs used to calculate the proposed case’s lighting power density. These figures were obtained from the COM check report and were used for the compliance calculation. [Figure 1.3.1 Lighting Schedule Breakdown] Fixture

Type

# of fixtures

Finelite S121D

direct/indirect

448

Finelight SF1

relocated stripfixture

256

HE Williams PV60

recessed can

520

Forecast F5562‐36

wall sconce

104

George Kovacs #P332

pendant

100

Total

fixture wattage

total watts

1428

The COM check review confirmed the table above and concluded that a total of 1,428 watts are present over 1,985 square feet, equaling a lighting power density of .7 w/sqft. To calculate this figure’s reduction in lighting power density, a space by space breakdown of allowed wattage requirements needs to be taken into account. Figure 1.3.2 shows a lighting power density breakdown for each space in the project and compares its reference wattage allowance with the COM check review’s numbers.

Area

Baseline

enclosed office other (bathroom, cooridor, storage) enclosed office other (bathroom, cooridor, storage)

total Propsed

Allowed Watts/sqft (ASHRAE 90.1 2001)

Floor Area 776 1209

total watts

1.5

1164

1209 2373

776

‐

1209

‐

total

‐

% reduction

‐

‐ ‐ 1428 (taken from figure 1.3.1) 39.90%

The overall lighting power density reduction for the proposed case against the ASHRAE 90.1 2001 reference standard came to 39.9%. Figure 1.3.3 shows the amount of eligible tax deduction based on the total lighting power reduction savings for the interim lighting rule. Given the proposed cases 39.9% percentage savings, this efficiency measure should certify the building for the full $.60/sqft tax deduction. [Figure 1.3.2 Eligible Tax Deduction Figures] % of LPD reduction beyond Standard 90.1‐2001 Amount of Eligible Tax Deduction/sq.ft.

25% $0.30

26%

27%

28%

29%

30%

31%

32%

33%

34%

35%

36%

37%

38%

39%

40%

>40%

$0.32 $0.34

$0.36

$0.38

$0.40

$0.42

$0.44

$0.46

$0.48

$0.50

$0.52

$0.54

$0.56

$0.58

$0.60

Section 1.4 Additional Certification Requirements The following information is intended to help guide the certification process and verify the requirements of the CBTD rules and regulations for quality control standards. 1.4.1 Field Inspection After the energy efficiency measures are installed and operating, the CBTD states that the following is required for the final certificate of certification: “A statement by the qualified individual that field inspections of the building performed by a qualified individual after the property has been placed in service have confirmed that the building has met, or will meet, the energy-saving targets contained in the design plans and specifications, and that the field inspections, were performed in accordance with any inspection and testing procedures that (1) have been prescribed by the National Renewable Energy Laboratory (NREL) as Energy Saving Modeling and Inspection Guidelines for Commercial Building Federal Tax Deductions and (2) are in effect at the time the certification is given.” The above mentioned qualified individual also has to certify that the lighting systems have been installed and that that each regularly occupied space has bi-level switching and meets minimum IES requirements. 1.4.2 Software Requirements

The software used for simulation must be included on the DOE published list of qualified software located here [www.eere.energy.gov/buildings/info/qualified_software]. Energy Plus version 5.0 software was used for the whole building cost method energy modeling and is included in this list of acceptable software programs. Similar weather files, internal loads, and building schedules were used for both the reference building and proposed case. The interim lighting rule does not require the calculation of energy and power costs for the entire building and therefore does not require the use of approved DOE software for this purpose. 1.4.3 Owner Notification Before the final certification letter is drafted, the writer of the letter must verify that the building owner has received an explanation of the energy efficient features of the building and its projected annual energy costs. For the interim lighting rule, the owner must be provided with an estimate of projected annual energy costs for the lighting system based on the total connected lighting system wattage, projected annual operating hours of the lighting system and the current electric rate of the property. The provision of this report to the building owner should suffice for this requirement. Additionally, once the systems are installed, a list containing all the components of the interior lighting systems, along with energy efficiency features, and projected annual energy costs must be attached to the certificate of compliance. Once all of the above measures are designed, installed, and inspected, the certifying engineer can complete the certification of compliance with boiler-plate statements that verify all of the above requirements of the CBTD.

Section 2 â&#x20AC;&#x201C; REAP Grant Section 2.1 Introduction The Rural Energy for America Program (REAP) helps small businesses in rural areas fund and pay for both renewable energy production and energy efficiency upgrades. The program can provide up to 25% of the cost of these improvements if the target projects meet certain requirements concerning energy savings, cost analysis, and other sustainability related issues. The energy efficiency measures (EEMs) under analysis for the parameters of the grant program include the following: -

upgraded windows radiant heating upgrades (in some cases) lowered lighting power density and daylight photocontrols stand alone energy recovery system night flush ventilation cross and stack ventilation tankless electric hot water system

A detailed discussion of these energy efficiency measures and their modeling parameters are described in the following section.

Section 2.2 Modeling Methodology 2.2.1 - Baseline Discussion The main parameters evaluated by the REAP grant proposal process include the following two categories: energy savings and return on investment. This report aims to show both energy and cost

savings for the different energy efficiency measures (EEMs) of the project, but compared against two different baseline cases. The first case compared the EEMs against the industry standard ASHRAE 90.1 2004 code baseline and its requirements concerning HVAC system, envelope requirements, scheduling, etc. The second case compared the different EEMs against the existing radiant heating HVAC system. This split comparison is due to the fact that because the project is a renovation, we have found that the existing HVAC system employed by the building is actually more energy intensive than the ASHRAE 90.1 standard, due to the lack of insulation under the radiant heating slab. Figure 2.2.1 shows the modeling parameters for both baselines used in this report. [Figure 2.2.1 Energy Modeling Baseline Parameters] Parameter square footage

ASHRAE 90.1 Baseline

Exisitng HVAC Baseline

3143 sqft

Pullman, WA .epw file

Unitary, dx cooling coil, gas heating coil

existing radiant system with electric boiler

lighting power density

1 w/sqft

equipment power density

.8 w/sqft

20 CFM/person

Domestic Hot Water System

Electric Water Heater

Infiltration Rate

0.000302 m3/s/m2

0.000302 m3/s/m3

weather file number of people

HVAC system

Ventilation Rate

Envelope Requirments

ASHRAE 90.1 except for ASHRAE 90.1 except for existing existing

2.2.2 - Radiant Heating For the baseline of the existing building, its current radiant heating system was modeled according to information provided by the architect of the project, which included a 5” thick hydronic radiant heating slab with an electric mini boiler and no insulation. The system also used constant set point of 72 degrees controlled by a regular air temperature thermostat. The results of the model showed that this existing system actually increased the heating energy consumption by 86% over the standard ASHRAE 90.1 2004 baseline, due to the lack of insulation under the slab and the constant set point temperature. Best practices concerning radiant heating systems in cold climates recommend a minimum of 2 inches of insulation board under the slab to ensure the heating energy within the insulated envelope of the building. This can be especially problematic during the wintertime due to the laws of thermodynamic heat transfer which indicate that the rate of heat loss through conduction is directly proportional to the increase in delta temperature between two surfaces. Consequently, the temperature difference between the slab and ground will be greater than between the slab and the indoor air, which will cause more of the energy created by the radiant system to transfer downward, not upward. Additionally, using a constant 72 degree Fahrenheit heating set point in conjunction with an air temperature-controlled thermostat to call for heating can be a relatively unresponsive and energy inefficient control system for radiant heating. This report tested different variations of radiant systems with different setback temperatures and underfloor insulation. The setback temperature strategy not only reduces system demand during unoccupied hours, but it also attempts to be sensitive to the concrete

floor’s thermal lag. Some advanced systems even use PID thermostatic controllers that have a built in intelligence which can learn the lag time of a system and adjust setback temperature schedules accordingly to avoid overheating and unnecessary energy use. This report tested setbacks that used a 62.6 degree Fahrenheit temperature during unoccupied hours between 22.00 until 4.00 before switching over to a 70 degree Fahrenheit set point during occupied hours. Also, the system employed a thermostat that used the mean radiant temperature of the space to call for heating, which can more directly respond to the changing radiant temperatures of the heating system and indoor environment. Figure 2.2.2 shows four different versions that test the relationship between heating setpoints, insulation, and their affect on the energy performance of a radiant system. [Figure 2.2.2 Radiant Heating Explorations]

[note: CSP and VSP stand for “constant set point” and “varied set point”, while INS stands for insulation] The study revealed that significant amounts of savings can occur if temperature setbacks are utilized during unoccupied hours of the day while accounting for the thermal lag of the system. Perhaps even more important is the insulation underneath the slab, which can drastically affect the efficiency of a radiant heating system by almost 50%. 2.2.3 - Upgraded Glazing Increasing the performance specifications of the glazing for the project created benefits for both heating and cooling energy performance. Figure 2.5.2 shows the different specifications between the existing and proposed glazing for the project. The chart shows the difference in specifications between the Baseline ASHRAE reference standard and the proposed glazing improvements. However, the fields that contain the name “Energy Model Inputs” represent the closest window assembly equivalent in the energy modeling software that was used for the simulation.

[Figure 2.2.3 Glazing Requirements and Specifications] Window Glass Specifications Baseline ASHRAE 2004 Code Requirements

U-Value

SHGC

0.57

0.49

Baseline Energy Model Inputs

0.55

0.50

Proposed Specified Glazing

0.32

0.28

Proposed Energy Model Inputs

0.29

0.25

Skylight Glass Specifications Baseline ASHRAE 2004 Code Requirements

1.17

0.49

Baseline Energy Model Inputs

1.08

0.60

Proposed Specified Glazing

0.53

0.24

Proposed Energy Model Inputs

0.50

0.25

The proposed glazing’s lowered solar heat gain coefficient value reduced the cooling energy by about 17.6% due to the large amount of glazing on the west side of the building. Given that the windows on this façade are un-shaded, increasing the SHGC of the building made a significant impact on the cooling energy in this zone. Additionally, the decreased U-value of the windows loses less heat to conduction from the cold Moscow winters, thereby decreasing the overall heating energy required for the building by around 8%. This report found that any efficiency measure that can gain a bonus in heating will lead to large savings due to the heating-dominated nature of the project’s climate. 2.2.4 - Upgraded Lighting Using the COM check information provided from the architect, this energy efficiency measure was modeling with a lowered lighting power density of .7 watts per square foot (about 30% better than the 2004 ASHRAE code requirement). The project’s lowered lighting power density was also modeled using a three step photocontrol system to maximize electrical energy savings. Photo sensors were placed in the middle of both zones of the model with a 100% threshold of 25 footcandles. The upgraded lighting system created a 50% decrease in both cooling energy and electric lighting energy. However, decreasing the amount of time the electric lights are on may have helped with the cooling energy of the building, but it was an insignificant bonus when looking at the 10% gain in heating energy due to the lack of waste heat generated by the lights while they are operating. Despite the heating penalty, the entire EEM still gained a net benefit of 5-8% overall energy reduction when looking at total energy use. 2.2.5 - Night Flush Ventilation To model the night flush ventilation system, an air flow rate had to be obtained from hand calculations to size the night ventilation for the building simulation. Figure 2.2.5.1 shows the parameters that were used for the hand calculations. [Figure 2.2.5.1 Night Flush Calculation Parameters] Mass Surface Area (SF) Mass Volume Mass Heat Capacity (Btu/F) Floor Area (SF) Building Volume (F3)

1600 528 11880 1600 24000

Mass Surface Conductance (btu/h ‐ ft2 ‐ F) Starting Mass temp (f)

1 80

The only source of mass in the building was contained in the floor slab, while the mass heat capacity and surface conductance were based on typical heavyweight concrete. The starting mass temperature of the building is the assumed end temperature of the mass that starts the night flush cycle when the building is opened. Figure 2.2.5.2 shows the temperature profile of the 99% ASHRAE design day of Moscow Idaho, and the constituent performance of the thermal mass system. [Figure 2.2.5.2 Night Flush Temperature Profile and Btu Cooling Capacity] Hour

Outside Air Temp (F)

Cooling Capacty (Btu)

Mass Temp (F)

Bld Mode

8:00 PM

8000

79.3 OPEN MODE

9:00 PM

6922.6

78.7 OPEN MODE

10:00 PM

71.6

11430.2

77.8 OPEN MODE

11:00 PM

14050.8

76.6 OPEN MODE

12:00 PM

16958.4

75.2 OPEN MODE

1:00 AM

25874.5

73.0 OPEN MODE

2:00 AM

60.8

19509.7

71.4 OPEN MODE

3:00 AM

5362.1

70.9 OPEN MODE

4:00 AM

4640.0

70.5 OPEN MODE

5:00 AM

4015.0

70.2 OPEN MODE

6:00 AM

3474.3

69.9 OPEN MODE

7:00 AM

‐4993.6

70.3 CLOSED MODE

8:00 AM

78.8

‐13601.1

71.4 CLOSED MODE

9:00 AM

82.4

‐17529.3

72.9 CLOSED MODE

The figure shows the relationship of the time of day, outside air temperature, and mass temperature on the overall cooling capacity of the mass. Once these calculations were complete, information about the hour of maximum cooling was extracted to find the air flow rate needed by the night flush system. To find the cubic feet per minute required to flush the system at night, the following two equations were used: CFH =

The final flow rate for the system proved to be 1,712 cubic feet per minute which equaled 4.2 air changes per hour. This flow rate could be met using either mechanical or passive means and the energy model reflects a negligible increase in fan usage from using an exhaust fan for night ventilation. The system used this ventilation rate from 22:00 until 7:00, right before occupied hours of the ASHRAE 90.1 office schedule. Additionally, the night flush schedule was found to save the most energy when used during July 15 and August 31, which avoided overcooling the space during shoulder seasons while maing the

most effect during peak cooling conditions. Even though this EEM showed cooling savings, they are quite small compared to the overall energy usage of the building due to the fact that this particular office program in Moscow uses very little cooling energy to begin with. The project is a small office building with a low window to wall area ratio and only six people, which does not equate to a large heat gain rate in a climate with only 762 average cooling degree days. Additionally, the most significant amount of cooling savings (50%) were already achieved in this energy model from the lighting and photocontrol systems. 2.2.6 - Natural Ventilation Despite the relatively small amount of savings available after the upgraded lighting and night flush ventilation EEMs, adding natural ventilation to the strategies still improved cooling energy performance. The strategy uses a combination of stack ventilation from electrically operable skylights and cross ventilation from side windows at the occupant level. The following equation can be used to find the combined flow rate for both strategies: = However, before this can be done, each individual flow rate for both cross and stack ventilation were found through detailed hand calculations. The two following equations were used to obtain these individual figures: = . 55

60 . 65 32.2

Given the window and skylight parameters of the project and a 3.2 average daytime wind speed, a total airflow rate of 5,566 CFM was calculated for the combined capacity of cross and stack ventilation. Even without the upgraded lighting system and thus decreased cooling load, this EEM eliminated relatively all the need for cooling between the middle of May and the beginning of October (excluding the times during night flush). This operation schedule was only used if the outdoor temperature was in between 67 and 75 degrees Fahrenheit to avoid overcooling or overheating the space. Additionally, the system was not active if the indoor temperature fell below 73.5 degrees Fahrenheit, right below the typical cooling set point of a baseline HVAC system. 2.2.7 - Energy Recovery Ventilation Stand alone energy recovery ventilation (ERV) is another EEM that decreased the heating energy of the project, thereby leading to significant energy savings. In terms of using the system for cooling, however, it conflicts with the natural ventilation strategy. Typically either natural ventilation or the energy recovery ventilator would be operating during the cooling season to take advantage of free cooling provided by certain outdoor air conditions. Most stand alone energy recovery ventilation units come equipped with an “economizer mode” or bypass valve that directs air around rather than through the plate or rotary heat

exchanger. Consequently for the purposes of this simulation report, the heating energy savings are shown for the ERV while the cooling savings are left to the natural ventilation and night flush system. The ERV unit that was originally specified did not show any savings and was actually shown to increase overall energy usage due to its over-sized CFM rate (560-690 CFM, when only around 150 is needed), sensible effectiveness percentages, and 640 watt power rating. After running the original simulation, an alternative unit was researched and modeled for comparison. Figure 2.2.7 shows the different performance specifications between the two units and their subsequent energy use: [Figure 2.2.7 Energy Recovery Ventilator Unit Comparison] 250,000

‐0.4%

9.3%

200,000

KBTU

150,000 Savings

100,000

Heating 50,000

‐

Existing_ ERV_Specified Radiant_Baseline

Thermal Effectiveness Rating

ERV_Proposed

Specified Sensible Latent eff. eff.

Upgraded Sensible Latent eff. eff.

100% Airflow Heating Condition

55%

91%

75% Airflow Heating Condition

61%

92%

100% Airflow Cooling Condition

47%

91%

75% Airflow Cooling Condition

53%

91%

Manufacturer Rated CFM Heat Exchanger Type Power Usage

RPG Group 560‐690 capacity

Fantech 160 capacity

plate

640 watts

50 watts

The new energy recovery ventilation EEM proved to be quite effective, capturing 72% savings of the total heating load contributed by ventilation according to the ASHRAE 90.1 baseline. However, this only translates to about a 2% total energy savings for the entire building because the ventilation load is so low due to the relatively small occupancy of the building. This EEM would be even more effective if the

occupancy load of the building was higher than six people, which would increase the overall contribution of ventilation to the heating load and lead to more energy recovery ventilation savings. 2.2.8 – Domestic Hot Water Upgrade This EEM tests the implementation of a tankless electric water heater versus the existing 50 gallon conventional system. After searching the manufacturers web site, the report concluded that the existing Bradford White electric hot water heater (model no. M250S6DS5) was rated at an 80% efficiency because of its age and model. The new tankless system specified by the architect is the EEMAX tankless hand washing water heater with a 5500 W capacity and a 99% efficiency. These specifications led to a 19% increase in efficiency for the domestic hot water system. 2.2.9 - No Air Conditioning System The last iterations of the report were run without an air condition system to reflect the owner’s thermal comfort intentions and goals. Currently, the space operates without any type of air conditioning system and the owner/future tenants of the space set the goal of the renovation to stay without mechanical cooling. Additionally, the ASHRAE 90.1 baseline results show that the cooling energy of the building is only 1% of the total energy use. The intention for this project was to provide passive cooling measures such as natural ventilation and night flush to increase the thermal comfort of the space over its already satisfactory performance. The building’s cool summer climactic conditions, low occupancy, low internal heat gains, and passive cooling measures should be enough to be able to satisfy most of the thermal comfort demands of the client and forego any type of mechanical cooling. Figure 2.2.9.1 shows the effect of night flush ventilation on reducing the indoor temperature during the peak summer design day for Moscow. [Figure 2.2.9.1 – Night Flush Temperature Profile] 95

Fahrenheit( degree F )

90 85 80 75 70

BASELINE_NoAC

NIGHT_FLUSH

60 55 50

time of day

Night flush ventilation was successful in cooling the space and made about a 7 degree Fahrenheit difference during the hottest part of the day while lowering the indoor temperature during all occupied hours. However, to understand just how effective night flush ventilation is when combined with natural

ventilation from the operablewindows, figure 2.2.9.2 shows the amount of occupied hours that exceed 80 degrees Fahrenheit during the cooling season. [Figure 2.2.9.2 – Number of Hours above 80 deg F] Cooling Season(May1st Sep30th) Total No of Occupied Hours No of Hours>80 degree F % hours >80 degree F

Baseline_No AC

Natural Ventilation & NightFlush

1989

579

29.1%

1.5%

With the passive cooling strategies and no mechanical cooling, only 1.5% of the total occupied hours are out of the comfort zone. This figure is acceptable and can be used to argue against the need for any type of conventional air condition system because of the minimal amount of time that is outside of the comfort zone. 80 degrees Fahrenheit was chosen as the temperature threshold even though 78 degrees Fahrenheit is the upper limit of the typical comfort zone. However, the ASHRAE standard 55.1 thermal comfort model was used to evaluate this particular criteria because of its comprehensive evaluation of comfort. This new thermal model takes into account comfort criteria that goes beyond mean air temperature and balances thermal comfort against radiant temperature, humidity, and air movement. Since thermal mass and night flush ventilation have a larger effect on the mean radiant temperature of the zone, these reduced radiant temperatures will balance out 80 degree air temperature and lead to thermal comfort.

Section 2.3. Energy Savings Case 1 - ASHRAE 90.1 2004 Baseline Savings The charts in Figure 2.3.1 show total energy savings for the project’s different EEMs in an additive manner, with each new version showings savings against the ASHRAE 90.1 2004 baseline including the previous EEMs added before that particular measure. In other words, the savings amount for each EEM is not the amount of energy it saves according to the previous EEM, but to the baseline column. [Figure 2.3.1 Total Energy Savings against ASHRAE 90.1 2004 Baseline] 350,000

‐35.2% 300,000

250,000

5.4%

8.1%

11.0%

23.8%

25.7% Savings Heating

200,000

Cooling

KBTU

Fans Pumps Heat Recovery

150,000

Interior Lighting Exterior Lighting Interior Equipment 100,000

Water Systems

50,000

‐ Baseline_ ASHRAE

in KBTU Heating

Upgraded_ Glazing

Baseline_ ASHRAE

Upgraded_ Glazing

139,737

Heating Savings(%) Cooling

Exterior Lighting Interior Equipment Fans Pumps

127,301 8.9%

2,531

2,085

29,335

Cooling Savings(%) Interior Lighting

Upgraded_ Lighting

17.6%

Upgraded_ waterheater

Night_ Flush

Natural_ Ventilation

Upgraded_ waterheater

Upgraded_ Lighting 136,761 2.1% 1,109 56.2% 14,540

136,761 2.1% 1,109 56.2% 14,540

Night_ Flush

Existing_ Radiant

Ideal_ Radiant

Natural_ Ventilation 136,789

Existing_ Radiant

136,827

2.1%

957

938

62.2% 14,540

ERV/Final

62.9% 14,540

Ideal_ Radiant

248,091 -77.5% No Cooling 62.9% 14,540

ERV/ Final

107,236 23.3% No Cooling 62.9% 14,540

100,402 28.1% No Cooling 62.9% 14,540

9,554

21,999

3,052

2,663

2,512

2,692

2,777

256

379

711

4,957

1,659

1,469

Heat Recovery

1,886

Water Systems

37,989

30,757

Total Total Savings(KBTU) Total Savings(%)

244,196

230,926

224,462

217,230

217,287

217,391

330,153

186,123

181,317

13,269.4

19,733.6

26,965.4

26,908.5

26,804.3

(85,957.5)

58,072.8

62,878.2

5.4%

8.1%

11.0%

-35.2%

23.8%

25.7%

The last “ERV/Final” column represents the final design package with all of the energy efficiency measures proposed by the architect, except that it uses the ideal radiant system versus the existing radiant system. As mentioned earlier in section 2.2.2 of the report, the existing radiant system’s lack of underslab insulation and constant set points proved to be detrimental to any baseline energy comparison. Consequently, this section of the report includes an EEM using an ideal radiant system with insulation, varied setpoints, and a radiant temperature control to understand potential savings of the system. The

final design package was found to attain 25.7% total savings over the ASHRAE 90.1 2004 baseline. Figure 2.3.2 translates this energy savings into cost savings based off the properties utility rate. [Figure 2.3.2 Cost Savings against ASHRAE 90.1 2004 Baseline] Electric (kWh)

Percentage Delta Cost($) Savings(%)

Cost($)

Baseline_ASHRAE

71,570 $

7,157 N/A

Upgraded_Glazing

67,681 $

6,768 $

389

Upgraded_Lighting

65,786 $

6,579 $

578

8.1%

63,667 $

6,367 $

790

11.0%

Night_Flush

63,683 $

6,368 $

789

11.0%

Natural_Ventilation

63,714 $

6,371 $

Existing_Radiant

96,762 $

9,676 $

(2,519)

-35.2%

Ideal_Radiant

54,549 $

5,455 $

1,702

23.8%

ERV/Final

53,141 $

5,314 $

1,843

25.7%

Upgraded_Waterheater

786

5.4%

11.0%

Assuming 1kWh=10 cents for Non Residential category The table shows electric kWh consumption for each EEM considering that electricity is the only fuel source for this set of comparisons. Additionally, the “Cost” column represents the annual energy bill for each case, while the “Delta Cost” column shows how much money is saved each year as a result of the EEMs. The table shows a potential 25.7% annual cost savings, or a total of $1,843 of savings per year. The next two figures disaggregate the heating and cooling energy of the building and analyze each EEM’s affect on the energy savings according to that particular end use. [Figure 2.3.3 Heating Energy Savings against ASHRAE 90.1 2004 Baseline 250,000

‐77.5%

200,000

150,000

KBTU

2.1%

8.9%

Savings

23.3%

100,000

Heating

28.1%

50,000

‐

Baseline_ ASHRAE

Upgraded_ Glazing

Upgraded_ Lighting

Night_ Flush

Upgraded_ Water_heater

Natural_ Ventilation

Existing_ Radiant

Ideal_ Radiant

ERV/Final

[Figure 2.3.4 Cooling Energy Savings against ASHRAE 90.1 2004 Baseline] 3,000

2,500

17.6%

56.2%

62.2%

62.9%

KBTU

2,000

1,500 Savings Cooling

1,000

500

‐

Baseline_ ASHRAE

Upgraded_ Glazing

Upgraded_ Lighting

Upgraded_ waterheater

Night_ Flush

Natural_ Ventilation

Existing_ Radiant

Ideal_ Radiant

ERV_ Final

Important things to note about the heating energy savings chart is that the amount of heating energy saved actually decreases during the lighting upgrade EEM. This is due to the dynamics between shutting of electric lights and losing the waste heat generated from the lighting fixtures as mentioned earlier in this report. Additionally, the last three EEMs of the cooling energy savings chart show a lack of any cooling energy (100% savings) due to the owner’s goal of requiring no mechanical cooling. The chart also shows that only a minimal amount of cooling energy is required by the building after the addition of the passive cooling EEMs. Although the 62.9% savings on cooling energy won’t save a large amount of absolute kBtus, not requiring an air conditioning system will save any and all first costs associated with not having to purchase mechanical cooling for the space.

Case 2 Existing Radiant Heating Baseline The charts in Figure 2.3.5 show total energy savings for the project’s different EEMs in the same additive manner as before, but this time energy savings are calculated against the first column which represents the existing radiant heating system in the project. [Figure 2.3.5 Total Energy Savings against the Existing HVAC Baseline] 350,000

5.8%

6.3%

7.9%

11.3%

7.9%

23.2%

300,000

250,000 Savings Heating

200,000

KBTU

Fans Pumps Heat Recovery

150,000

Interior Lighting Exterior Lighting Interior Equipment

100,000

Water Systems

50,000

‐

Existing_ Radiant_Baseline

in KBTU Heating

Upgraded_ Glazing

Exterior Lighting Interior Equipment

Upgraded_ Water_heater

Existing_ Upgraded_ Upgraded_ Radiant_Baseline Glazing Lighting 242,954

Heating Savings(%) Interior Lighting

Upgraded_ Lighting

221,325 8.9%

29,335

237,769 2.1% 14,540

Night_ Flush

Natural_ Ventilation

Upgraded_ Night_ Waterheater Flush 237,769 2.1% 14,540

Energy_Recovery_ Radiant_Varied_ Ventilator Setpoints

Natural_ Ventilation

237,817 2.1% 14,540

237,874 2.1% 14,540

Energy_Recov Radiant_Varied ery_Ventilator Setpoints/Final 220,225 9.4% 14,540

179,782 26.0% 14,540

9,554

21,999

284

247

233

249

257

4,635

4,483

5,080

4,815

4,957

4,388

3,696

Heat Recovery

1,886

Water Systems

37,989

30,757

347,195

325,263

327,041

319,809

319,872

319,937

307,984

266,697

21,931

20,154

27,386

27,323

27,258

39,211

80,498

Fans Pumps

Total Total Savings(KBTU) Total Savings(%)

6.3%

5.8%

7.9%

11.3%

23.2%

It is worthwhile to note that this series of charts do not have any cooling savings due to the lack of a cooling system in both the existing building and proposed EEM measures. To understand how much energy the passive cooling EEMs saved, Figure 2.3.1 has to be used. The last column, “Radiant_Varied_Setpoints/FINAL”, represents the final design package that would be the easiest to implement given the existing condition of the building. This final additive measure also showed how more energy savings can be achieved by working with the non-ideal existing radiant system of the building. By adjusting the set points and potentially investing in a better control system, additional savings can be realized on top of the other EEMs. The total package has the potential to save 23.2% of the overall energy when compared to the existing radiant baseline. Figure 2.3.6 shows the amount of cost savings potential for this EEM package against the existing radiant system of the building.

[Figure 2.3.6 Total Cost Savings against the Existing HVAC Baseline] Electric (kWh) Existing_Radiant_Baseline

Cost($)

101,757.0 $

Percentage Delta Cost($) Savings(%)

10,176 N/A

Upgraded_Glazing

95,329.2 $

9,533 $

643

6.3%

Upgraded_Lighting

95,850.1 $

9,585 $

591

5.8%

Upgraded_Waterheater

93,730.6 $

9,373 $

803

7.9%

Night_Flush

93,749.2 $

9,375 $

801

7.9%

Natural_Ventilation

93,768.1 $

9,377 $

799

7.9%

Energy_Recovery_Ventilator

90,264.9 $

9,026 $

1,149

11.3%

Radiant_VariedSetpoints/Final

78,164.4 $

7,816 $

2,359

23.2%

Assuming 1kWh=10 cents for Non Residential category

In this case, a total savings of 23.2% translates to $2,359 in annual savings against an all electric HVAC system. Without the last EEM, only slightly more than $1,000 is realizable through the design package. This is due to the lack of any cooling energy savings, leaving only the upgraded glazing and energy recovery ventilator to achieve any energy efficiency. As mentioned earlier, the energy recovery ventilator would be much more effective in a situation with more occupancy load and thus more ventilation requirement. Additionally, as Figure 2.3.7 shows, the total amount of heating savings would also be greater without the heating penalty incurred from the lighting upgrade. However, as shown in the cost analysis, the upgraded lighting saves as much cost through its electrical lighting energy savings that offsets with increased heating. If cooling were taken into account, this EEM would create a net benefit in terms of cost. Despite the lack of an air conditioning system, the proposed EEMs have the potential to save 26% of the heating energy within the existing radiant heating system, which translates to an overall 23.2% total energy savings. [Figure 2.3.7 Total Heating Energy Savings against the Existing HVAC Baseline] 250,000

2.1%

2.1% 9.4%

8.9% 200,000

26%

KBTU

150,000

Savings Heating

100,000

50,000

Existing_ Radiant_Baseline

Upgraded_ Glazing

Upgraded_ Lighting

Night_ Flush

Upgraded_ Water_heater

Natural_ Ventilation

Energy_ Radiant_ Recovery_Ventilator Varied_Setpoints/Final

2.5 Conclusion This energy modeling report had two main goals for the overall building project. The first goal was to show that the project could achieve that Commercial Building Tax Deduction based on its lighting energy efficiency upgrades. The certification pathway required the project to show a 16 2/3% total energy and power cost savings as a result of the lighting efficiency upgrades, however this figure was not able to be achieved. The decreased lighting power density and continuous photocontrol system increased the total energy usage by 4.7% because of the heating-dominated nature of the building. The 11.2% savings that came from this upgrade is not enough to achieve certification. However, if the CBTD required a reduction in only lighting energy and power cost, then the 68% reduction would definitely qualify. Regardless, the second compliance pathway documented in the report shows that the required lighting power density reduction by the proposed case can potentially be certified for the highest amount of eligible tax deduction. The 39.9% reduction qualifies for the full $.60/sqft tax deduction, given the systems are installed as designed and verified on site after implementation. The second goal of the report was to provide information that the architect could use to submit an application to attain a Rural Energy for America Program grant for the project. The grant funding process weighs the “energy saved” and “design and engineering” categories highly in the overall scoring of the projects. Obtaining energy audits and meeting state environmental standards are also high on the list for scoring. This report aimed to provide information that documents energy and cost savings as a result of the multiple energy efficiency measures designed and engineering for the proposed building. Depending on which baseline served as the comparison, a 25.7% total energy and cost savings was possible through the EEMs that targeted heating, cooling, and lighting efficiency measures. Given the heatingdominated nature of the climate and the low internal loads of the building program, EEMs that targeted heating provided the most effective energy savings. Additionally any type of natural ventilation and cooling strategies did not see any cooling energy savings because of the lack of AC in the existing baseline, but proved to provide a more thermally comfortable environment based on the owner’s thermal comfort requests. Overall, a combination of the implementation of high efficiency HVAC systems, the integration of passive systems, and the usage of technical prowess in lighting efficiency upgrades all created significant energy savings for the renovation project.

Report written and coordinated by: Jacob Dunn – LEED AP Enlight Design LLC

_______________________________

date: 09.24.2010

Contact Information: info@ENlightDesignLLC.com 208.230.6077