Building energy performance
BCIT Niki jalali A01017134
Building energy Performance Analysis
Prepared For:Bo Li
Prepared By:Niki Jalali
1 Introduction 3
1.1 Project objectives: 4
1.2 Characterization of the baseline model 4
1.3 Building envelop and HVAC system of baseline 5
1.3.1 Building envelop 5
1.3.2 HVAC system 6
1.3.3 Baseline correction 7
2 Methedology 8
2.1 eQuest 3.65/BCIT energy performance lectures/ASHRAE 8
3 Energy Conservation Measures 9
3.1 Building Envelop: 9
3.1.1 Improve Window Thermal Performance 9
3.1.2 Improve Exterior Insulation 11
3.2 Electrical Energy conversation measure 13
3.2.1 Reduced Lighting Power Density (LPD) 13
3.3 Mechanical Energy consumption measures 15
3.3.2 Heat Recovery Ventilators (HRV) 15
3.3.3 Domestic hot water tank efficiency 15
3.3.4 Reduced Energy Input Ratio 16
3.3.6 Air Economizer 17
4 Integrated Measurement 18
5 Conclusion 20
6 References 22
Buildings are very complex objects, because they have interaction both with surrounding and inner conditioned area, while trying to maintain a comfortable environment for its occupants. The way a building can control the thermal comfort is to design a high performance building envelope and subsequent HVAC systems. It can be observed that the indoor environment condition is a factor of many exterior and energy resources, which provides the thermal comfort and better indoor air quality for the occupants of the building. The design of a new building can be a difficult task due to complexities. Purpose of this project is to using three main categories energy conservation measures (ECMs) to save the overall 20percent energy consumption .the strategy which have been implemented in this project are building envelope, electrical components and mechanical equipment. Several ECMs have been investigated throughout this semester .all analysis have been performed using eQuest version 3.65. All simulations have been performed using the parametric run feature in eQuest to illustrate and compare the differences each ECM has, with respect to the baseline model. The top 4 ECMs have been selected to become the proposed overall energy reduction strategy (20%).The monthly total energy consumption reports and the annual energy reports were used to compare to the baseline. Percent reductions in energy are calculated based on the amount of overall MBTU reduced compared to the baseline energy consumption of 844.5 MBTU. These overall MBTU values have been retrieved from the detailed output reports. The building energy consumption has also been corrected to account for the originally incorrect parking lot exhaust fan consumption.
[bookmark: _Toc4259263]Project objectives:
The purpose of this project is:
1) To find the potentials energy conservation measures for a 4 story office.
2) to develop a model to consume 20% less energy compared the baseline
3) Effect of each ECMs on the energy consumption of baseline.
[bookmark: _Toc4259264]Characterization of the baseline model
There are several methods that can be effective to improve building energy consumption of a commercial 4 story building. The main techniques are covered in building energy performance course. In this project the baseline building is a office building, assumed located in Vancouver (3000HHD) [According to HOF]-(winter outdoor temperature19F – summer outdoor temperature 70F).
The building is a 78.9ft X78.9ft which give us a total area of 24900 square feet. Baseline building consist of3 level offices and consist of a basement which is used as a packaged for vehicles.
[bookmark: _Toc4259265]Building envelop and HVAC system of baseline
[bookmark: _Toc4259266]Building envelop
The building is 12feet floor to floor. It has a flat roof consisting of 6” of concrete with gravel ballast and 4” of continuous polyisocyanurate insulation and constructed with concrete slab over top of a parkade basement. The windows are 5 feet high, single pane low-e(type1600), aluminum frame. The window to wall ratio is 53.3% on each of the elevations. There is an exterior door on each orientation of the main floor with the dimensions of 7 by 8 feet, which is also single glazed, low-e glass.
The overall exterior wall is steel framed consisting of the
Following materials from outside to inside:
1) 1” thick Stucco (medium colour)
2) 5/8” exterior gypsum board
3) 1” thick polystyrene continuous insulation
3) 3.5” steel studs at 16” o.c.
5) R-13 batt insulation in the cavity
6) 1/2” interior gypsum board.
The U value for each of the building envelope systems can be observed in Table below with the supplemental requirements as per ASHRAE 90.1 .
Ex wall above grade
Ex wall below grade
[bookmark: _Toc4259267]HVAC system
The HVAC system in the baseline is a single-packaged with direct exchange coil system and furnace. The cooling system range a 135 – 240 kBtu system which is air cooled and has a EER of 11. The condenser attached to the chiller is air cooled. The heating system is a 225 kBtu with 80% efficiency. The office has a domestic hot water loop as per an outside source. In order to meet occupancy thermal indoor air requirements the heating is set at 70 F with a setback of 64 F, while the cooling is set at 76 F with a setback of 82 F. The building is divided to five zones on each floor in order to provide for occupant thermal comfort. In order to provide adequate indoor air quality ventilation was provided to each of the zones. The building also contains an air cooled condenser to convert stream from its gaseous stage to its liquid stage. It uses outdoor air to provide cooling efficiencies to the building.
Figure 3- Baseline HVAC System for the Office Building as seen in eQuest
[bookmark: _Toc4259268]Baseline correction
The baseline building model has been corrected which very high exhaust fan consumption according to the figure2 .this problem happened because of the non-decimal ratio. Typically the ratio of the fan should not be greater than 1 and according to model the entered parameters are not in decimal so they have to been divided by 100.figure 1 shows the consumption after correction .figure 2 shows consumption before correction.
Figure1 after exhaust fan correction
Figure2 before correction
[bookmark: _Toc4259270]eQuest 3.65/BCIT energy performance lectures/ASHRAE
eQUEST is a building energy analysis software “,DOE 2 engine with wizards and graphics built on top of it. eQUEST is one of the most popular energy modeling program in existence. eQuest provides high quality results by combining a building creation wizard, an energy efficiency measure wizard and a graphical results .eQuest also offers life cycle analysis based on cost estimating, and energy efficiency measures.It completes simulations by calculating hour-by hour building energy consumption over an entire year. It provides a accurate simulation of building features such as shading, fenestration, interior and exterior building envelop , heating and air conditioning systems hot water loop .
In this project the simulation process starts with developing a model of the building in order to provide a baseline output for energy savings. Simulations can then be ran based on a number of energy conservation measurements in order to find the effect of each ECMS on saving . This can then be used to determine lifetime payback, life cycle analysis and overall energy savings.
[bookmark: _Toc4259271]Energy Conservation Measures
Energy conservation measures are categorized as any change to the model which can improve the buildingenergy performance .The three main categories energy conservation measures used are building envelop, electrical components and mechanical components. The purpose of this project is find one or several energy conservation measures to reduce 20 of total energy consumption of this building..All simulation is in detailed mode and to compare the different EMC techniques the parametric simulation run is used. The most top effective EMCs have been selected for reduction of total energy consumption. For each strategy one run is performed and the annual and monthly reports are used to compare the different strategy.At the end In order to better summarize the total energy usage of the building it is more effective to use an integrated measurement approach .The baseline total energy consumption is 844.5 MBTU which is specified in the detailed report .all comparison is based on this value.
[bookmark: _Toc4259272]Building Envelop:
[bookmark: _Toc4259273]Improve Window Thermal Performance
Builidng envelop has several parts, increasing the efficincy of these components possibly can reduce energy consumption . In the first step changing the windows type is one of the most ancipated strategy in energy consumption reduation ..figurebelow shows the electrical and gas consmuption after changing window type . existed glazing just meets the requirements of ASHRAE 90.1 with a thermal transmittance factor of 0.45 .For the purpose of the effectively reducing the energy consumption a range of fenestration options are consideredand. finally the optimume glazing system is selcted .The summery of final calculations is shown below. The window type for baseline building was single pane low E (1600) . The new type window ( double glazed with argon gas is replaced )
The new total energy consumption is 745.6 MBTU .
98.9/844.5= 0.117 11.7% redustion in total energy consumption
It can be seen that changing the window type is one of the most effective method to decrease overall energy consumption of this building . it has been understood from resluts that annual space heating energy consuption decresed from 278MBTU to 146MBTU but annual electrical consumption is incresed from 458MBTU to 520MBTU .This might be because of more need of ventilation and cooling to cool down the amount of heat in the building which could be conducted through single pane naturally in the baseline model. In this project the overall energy consumption is considered so although the eletrical enegy consuption increaesd the overall value decreased. In The second step changing insulation type possibly has a significant effect on energy reduction too
[bookmark: _Toc4259274]Improve Exterior Insulation
Building envelope above grade does not meet the requirements according to ASHRAE 90.1 and therefore changing the exterior board insulation is essential . The baseline U-factor was 0.087 Btu/h.F.ft2. By changing exterior insulation the building envelope the thermal resistance of the wall increases .As a result reducing the flow of heat through the wall means that the space heating of the occupied space will be reduced as more energy will not be needed to replace heat that is lost. In baseline, exterior wall components consist of stucco (1inch) Polystyrene , EL1 EWALL Cons Mat which is combination of stud and batt insulation and 1/2inch gypsum board. The overall u value in this case is .087(Btu/F.ft^2.h). Now the new wall assembly consist of ========================================================================= and the new u value is 0.79 (Btu/h.F.ft2. )
Unfortunately the E quest has limited option of high R value insulation for 2X4 studs. In this situation. The overall R value of 2X6 stud with R 19 insulation is calculated and as a reference is replaced with baseline R value.
The summary of changes in overall energy consumption is:
The new proposed envelope will consider implementing a range of board insulation thicknesses, both with and without an airspace (Appendix B). By introducing an ventilated air space, along with building paper as an air barrier, the infiltration loss will also be reduced, along with reducing the risk of moisture entrapment within the building enclosure. The sensitivity analysis of the various building envelope exterior insulation components will allow a best fit foroptimizing the energy building performance reduction
It can be seen Changing the wall insulation R value make around 2.9 percent reduction in overall consumption and about 9 percent reduction in space heating consumption .
· Quick Note: it should be considered that during changing or improving the opaque components the other parameters remain same as baseline. For instance in this scenario window types or other wall layers are same as baseline.
[bookmark: _Toc4259275]Electrical Energy conversation measure
According to the baseline simulation there are two main electrical components capability are simulated. First lightening types and second HVAC fan system.
[bookmark: _Toc4259276]Reduced Lighting Power Density (LPD)
The installed lighting power density has to be reduced significantly due to the installation of occupancy lighting sensors, light dimmers and timers. This can effectively reduce the LPD by 20% (ASHRAE, 2013). Reduced LPD will result in significantly less electrical use for lighting. Lightening power density for baseline model has been calculated using the maximum value of ASHREA LPD table. The parking lot LPD is 0.2 w/ft2 and office spaces is 96-98w/ft2. Based on Appendix1 documents, this can be improved by using Light Emitting Diode (LED) type fixtures which consume as much as 45 % less electricity. A typical T-8 fluorescent fixture consumes approximately 32W whereas an equivalent LED fixture with a comparable output lumen performance only consumes ~5-6W. The LPD values for the baseline have all been reduced by 45 % assuming that the equivalent lighting lumens can be met using LED type fixtures and adjustments in design and fixture placement. This is a significant reduction in energy consumption. Base on new technology in market using the LED lights can decrease LDP value to 0.18 w/ft2. The new simulation has been run.
New overall energy consumption: 782.0MBTU
The baseline overall energy consumption: 844MBTU
7.6 %saving overall energy consumption.
The detailed report shows electrical energy consumption decreased from 458.6 to 329.1 and gas consumption increased from 358.9 to 451 but the overall consumption dropped. The gas consumption increased because in the reality more LPD lightening produce more heat which make the space warm and as a result we need to provide more heat to keep the thermal comfort low LDP lightning eliminate producing this heat . The basement lightening cannot be replaced by the LED because it is very cost effective and as an economical view point is not much saving
[bookmark: _Toc4259277]Mechanical Energy consumption measures
There is several mechanical HVAC equipment that is used in this commercial office baseline. Several method are available to reduce the energy consumption by changing the efficiency of this equipment or adding new component to the HVAC system. Adding economizer and energy recovery ventilator, changing the domestic hot water efficiency are the examples of energy reduction method.
[bookmark: _Toc4259279]Heat Recovery Ventilators (HRV)
The baseline model does not have heat recovery for outside air .Heat recovery ventilators make use of an air-to-water exchanger which creates a heat exchange between the inbound and outbound air flow. This effectively reduce heating and cooling requirements. The eQuest input offers five distinct types of HRV systems.
· Sensible HX
· Enthalpy HX
· Sensible wheel
· enthalpy wheel
· Heat pump
For the purpose of optimization, all five were computed and analyzed in order to determine optimal energy efficiency. Finally the enthalpy wheel has been selected.
11.65% saving the energy consumption
[bookmark: _Toc4259280]Domestic hot water tank efficiency
The baseline building HIR ( heat input ratio is 1.37 . this premature has been calculated for a typical commercial grade gas fired hot water tank . the efficiency is 1/1.37=75% . the more efficient model of hot water tank can be replaced with efficiency of 95% which provide 1.05 HIR . to make sure that heat capacity is comparable the maximum value of 199btu/h replaced with 197BTU/H in the baseline .
18.1/844=.023 2.3 % saving in overall energy consumption.
It can be seen that compare to the other ECMs methods changing the efficiency of hot water does not have a significant effect on energy saving . This is because for a typical commercial building such as the baseline model analyzed, the use of hot water is much less than that of an equivalent sized residential building. Hot water showering and cooking constitutes the majority of the use of hot water in a building and there is limited use of this in a typical office environment.
[bookmark: _Toc4259281]Reduced Energy Input Ratio
The cooling energy input ratio (EIR) represents the packaged air cooling equipment (compressor and condenser) energy allowed in the system over the amount of energy exported within the system. It is directly related to the coefficient of performance of the system .therefore is a measurement of the system efficiency. The baseline model uses a COP of 3.846, which is just above the regulations set out by ASHRAE 90.1. In order to effectively optimize the energy performance of the cooling unit, a COP of 5 will be used in order to assess the energy building performance reduction.
0.84% saving in overall energy consumption
[bookmark: _Toc4259283]Air Economizer
The air side economizer in the baseline model has been changed for operation from fraction of design flow control to a demand-controlled ventilation (DCV) zone sensor control. A DCV control scheme adjusts the amount of outside air delivered to a space based on the need / quantity of occupants. Input from a single CO2 sensor or a group of sensors is used as a control measure. Specifically, the option in eQuest to set by critical zone was selected. The compressor lockout feature was also disabled and has been selected as NO. As can be seen from the results above, a 4.9% savings in overall MBTU energy consumption was possible. Specifically, from the monthly energy consumption by enduse reports, the annual electrical consumption for space cooling has decreased from 5″,200 kWh to 2″,770 kWh. This is due to the lockout compressor feature being turned off. The annual gas consumption for space heating decreased from 277 MBTU to 235 MBTU. This result is in-line with the purpose of using an air economizer since when the outside air is cooler than the indoor control temperature, the cooling system is not used and the outside air is brought into the system to help cool the building (free cooling). Therefore, an air-side economizer reduces both space cooling and space heating if the compressor lockout feature is disabled. This ECM can be seen to be a good overall ECM.
[bookmark: _Toc4259284]Integrated Measurement
Some ECMs are more sustainable, an integrated measurement was completed where various ECMs were compiled together in order to assess the functionality on one another. Table below gives an overview of the integrated ECMS.
Increasing the R value of insulation
HRV – Enthalpy HX
Domestic Hot Water Tank – Efficiency Increase
It can be observed that by increasing the window performance the energy consumption is reduced by 11.7%and adding an HRV by approximately 12%. However, when all energy conservation measurements are implemented together they only reduce the energy consumption by 27%. This is due to the integrated effect that systems have on other building components. Adding a HRV system increases the electricity consumption above the baseline, but it reduces the natural gas consumption. While on the other hand reducing the lighting power density had the opposite effect, effectively having a neutral effect.
For this project (small liquor store), which is modelled in eQuest, from the baseline simulation using 7 energy conservation measures, the overall building performance is improved by 27% The integrated analysis took ECMs that were denoted to being sustainable and applying .then they are simulated to the baseline model. As a recommendation for future implementation and design of the building is to complete a further analysis in order to complete a complete life cycle analysis. This life cycle analysis could help to determine the effective payback periods of ECMs both on their own, and integrated together. The analysis would help to further analyze the sustainability of ECMs against the baseline building model. The effective life cycle analysis for 20 years could then be computed in order to determine the future worth of the building. Also it should be considered that more ECMs can be simulated such as the reduction of thermal bridging, by analyzing the linear transmittance of the building envelope, changing the roof wall assembly , changing the airside system from single packaged to another type of airside systems . By analyzing more ECMs a greater building performance could be achieved.
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