Page 114 - Zero Net Energy Case Study Homes-Volume 1

CASE STUDY NO. 5
COLONIAL HOUSE MULTI-FAMILY HOUSING
Energy Design Analysis and Energy Performance
Modeling versus Post-Occupancy Measurement
Energy Modeling
Energy Pro modeling software, approved by the California Energy Commission (CEC) for show- ing compliance with state energy standards for residential projects, was used to estimate the en- ergy performance of the Colonial House project. Because of the affordable housing component, a project-specific utility allowance was required to be calculated for each unit, which is included in the maximum-allowable rent calculation. This is done using a CEC-mandated software tool known as the California Utility Allowance Calculator (CUAC)6.
The energy modeling results using the CUAC-prescribed input values for the project as a whole and the average 3BR unit are shown on the folllowing pages, broken down by category of energy use (heating, cooling, lighting, plug load and domestic hot water (DHW). Both total annual and monthly modeling results for all units taken together are shown on the opposite page..
Energy Use—Monitoring and Measurement
Each one of the 44 units is individually monitored for energy use along with the energy produced by the large solar PV array. This data has been recorded routinely since 2014. When the total monthly energy consumption of all units of housing are tabulated for 2015, the results are as shown in the chart below. This can be compared with the energy modeling results for all the units of housing taken together, shown on the opposite page (bottom).
6 The U. S. Internal Revenue Service (IRS) regulates the application of the Low Income Hous- ing Tax Credit (LIHTC) for affordable housing projects and has authorized the use of CUAC in California to determine the utility allowances. See http://www.gosolarcalifornia.ca.gov/afford- able/cuac/index.php.
Measured Monthly Energy Use
Measured Monthly Energy Use - All Units
All Units
(2015)
2.00 1.80 1.60 1.40 1.20 1.00 0.80 0.60 0.40 0.20 0.00
Jan Feb Mar 2015
Apr May Jun
Jul Aug Sep Oct
Nov Dec
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Zero Net Energy Case Study Homes: Volume 1
kBtu/sq.ft.