ASHRAE Journal - February 2011 - 68

solar NZEB projEct	
2.5 W/m2 (0.79 Btu/h·ft2). The uninsulated floor with variable interior ambient temperature (Case 3) has ground heat transfer levels that vary by a factor of four, with a significant shift of ground cooling to the summer months. Figure 5 compares the electrical energy consumption of Equinox House for the varying ambient temperature (Cases 3 to 6); representing the ICF foundation without insulation, a perfectly insulated floor, and the ICF foundation with 150 mm and 300 mm (6 in. and 12 in.) of underslab Styrofoam insulation. The electrical energy requirements include internal energy generation (humans, appliances, etc.), ventilation and infiltration loads, and building shell loads, in addition to the effects of ground heat transfer. Although the temporal variation of ground heat transfer is significant for the different cases, the impact on electrical energy consumption is not so great. The seasonal variation of ground heat transfer shown in Figure 4 caused by the slight variation of thermostat settings enhances the performance of the earth coupling to the house, minimizing both summer and winter loads in a manner favorable to utilities. Table 1 also lists the energy demand for the variable interior ambient temperature (Cases 3 to 6) along with the estimated cost and solar panel surface area required for the solar array. The insulation cost is shown in the last column. The cost for perfect insulation (Case 4) is not specified, but given for perspective on the house electrical energy impact. As seen from the results, spending $5,000 and $10,000 to insulate 150 mm and 300 mm (6 in. and 12 in.) under the floor reduces overall house electrical energy by 60 and 130 kWh/yr, respectively. In contrast, spending $1,875 for the ICF foundation reduced electrical energy by 370 kWh/yr. The additional savings in solar system cost due to slab insulation is $275 and $550 for Cases 5 and 6. The assumption of a solar system replacement every 20 years favors the insulated foundation wall with no underfloor insulation for our climate. So, that is why Equinox House has no insulation below the floor. Our results pertain to our region in Central Illinois. Depending on the region, the answer to ground insulation design can change drastically. It is an important question to answer correctly as the design choices can have a great effect on house construction and energy costs.

references
1. Deru, M.P., A.T. Kirkpatrick. 2001. “Ground-Coupled Heat and Moisture Transfer from Buildings; Part 1: Analysis and Modeling.” National Renewable Energy Laboratory. 2. Deru, M.P., A.T. Kirkpatrick. 2001. “Ground-Coupled Heat and Moisture Transfer from Buildings; Part 2: Application.” National Renewable Energy Laboratory.

Ty Newell is vice president of Newell Instruments and professor emeritus of mechanical engineering at the University of Illinois, and Ben Newell is president of Newell Instruments in Urbana, Ill.

www.info.hotims.com/33861-12

www.info.hotims.com/33861-43

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ASHRAE	Journal	

	

	

February	 2011



ASHRAE Journal - February 2011

Table of Contents for the Digital Edition of ASHRAE Journal - February 2011

ASHRAE Journal - February 2011
Contents
Commentary
Industry News
Letters
Meetings and Shows
Feature Articles
Thermal Coupling of Cooling and Heating Systems
10 Common Problems in Energy Audits
Hall of Fame Feature: History of the Changing Concepts in Ventilation Requirements
A Guide to Wireless Technologies
Building Sciences
Solar NZEB Project
Emerging Technologies
People
Special Section
InfoCenter
Commissioning
Products
Washington Report
Classified Advertising
Advertisers Index
ASHRAE Journal - February 2011 - ASHRAE Journal - February 2011
ASHRAE Journal - February 2011 - Cover2
ASHRAE Journal - February 2011 - 1
ASHRAE Journal - February 2011 - 2
ASHRAE Journal - February 2011 - Contents
ASHRAE Journal - February 2011 - Commentary
ASHRAE Journal - February 2011 - 5
ASHRAE Journal - February 2011 - Industry News
ASHRAE Journal - February 2011 - 7
ASHRAE Journal - February 2011 - Letters
ASHRAE Journal - February 2011 - 9
ASHRAE Journal - February 2011 - 10
ASHRAE Journal - February 2011 - 11
ASHRAE Journal - February 2011 - 12
ASHRAE Journal - February 2011 - 13
ASHRAE Journal - February 2011 - 14
ASHRAE Journal - February 2011 - 15
ASHRAE Journal - February 2011 - Meetings and Shows
ASHRAE Journal - February 2011 - 17
ASHRAE Journal - February 2011 - Thermal Coupling of Cooling and Heating Systems
ASHRAE Journal - February 2011 - 19
ASHRAE Journal - February 2011 - 20
ASHRAE Journal - February 2011 - 21
ASHRAE Journal - February 2011 - 22
ASHRAE Journal - February 2011 - 23
ASHRAE Journal - February 2011 - 24
ASHRAE Journal - February 2011 - 25
ASHRAE Journal - February 2011 - 10 Common Problems in Energy Audits
ASHRAE Journal - February 2011 - 27
ASHRAE Journal - February 2011 - 28
ASHRAE Journal - February 2011 - 29
ASHRAE Journal - February 2011 - 30
ASHRAE Journal - February 2011 - 31
ASHRAE Journal - February 2011 - 32
ASHRAE Journal - February 2011 - 33
ASHRAE Journal - February 2011 - Hall of Fame Feature: History of the Changing Concepts in Ventilation Requirements
ASHRAE Journal - February 2011 - 35
ASHRAE Journal - February 2011 - 36
ASHRAE Journal - February 2011 - 37
ASHRAE Journal - February 2011 - 38
ASHRAE Journal - February 2011 - 39
ASHRAE Journal - February 2011 - 40
ASHRAE Journal - February 2011 - 41
ASHRAE Journal - February 2011 - 42
ASHRAE Journal - February 2011 - 43
ASHRAE Journal - February 2011 - A Guide to Wireless Technologies
ASHRAE Journal - February 2011 - 45
ASHRAE Journal - February 2011 - 46
ASHRAE Journal - February 2011 - 47
ASHRAE Journal - February 2011 - 48
ASHRAE Journal - February 2011 - 49
ASHRAE Journal - February 2011 - Building Sciences
ASHRAE Journal - February 2011 - 51
ASHRAE Journal - February 2011 - 52
ASHRAE Journal - February 2011 - 53
ASHRAE Journal - February 2011 - 54
ASHRAE Journal - February 2011 - 55
ASHRAE Journal - February 2011 - 56
ASHRAE Journal - February 2011 - 57
ASHRAE Journal - February 2011 - 58
ASHRAE Journal - February 2011 - 59
ASHRAE Journal - February 2011 - 60
ASHRAE Journal - February 2011 - 61
ASHRAE Journal - February 2011 - Solar NZEB Project
ASHRAE Journal - February 2011 - 63
ASHRAE Journal - February 2011 - 64
ASHRAE Journal - February 2011 - 65
ASHRAE Journal - February 2011 - 66
ASHRAE Journal - February 2011 - 67
ASHRAE Journal - February 2011 - 68
ASHRAE Journal - February 2011 - 69
ASHRAE Journal - February 2011 - Emerging Technologies
ASHRAE Journal - February 2011 - 71
ASHRAE Journal - February 2011 - 72
ASHRAE Journal - February 2011 - 73
ASHRAE Journal - February 2011 - 74
ASHRAE Journal - February 2011 - 75
ASHRAE Journal - February 2011 - People
ASHRAE Journal - February 2011 - 77
ASHRAE Journal - February 2011 - InfoCenter
ASHRAE Journal - February 2011 - 79
ASHRAE Journal - February 2011 - 80
ASHRAE Journal - February 2011 - 81
ASHRAE Journal - February 2011 - 82
ASHRAE Journal - February 2011 - 83
ASHRAE Journal - February 2011 - 84
ASHRAE Journal - February 2011 - 85
ASHRAE Journal - February 2011 - Commissioning
ASHRAE Journal - February 2011 - 87
ASHRAE Journal - February 2011 - 88
ASHRAE Journal - February 2011 - 89
ASHRAE Journal - February 2011 - 90
ASHRAE Journal - February 2011 - Products
ASHRAE Journal - February 2011 - Washington Report
ASHRAE Journal - February 2011 - Classified Advertising
ASHRAE Journal - February 2011 - 94
ASHRAE Journal - February 2011 - 95
ASHRAE Journal - February 2011 - Advertisers Index
ASHRAE Journal - February 2011 - Cover3
ASHRAE Journal - February 2011 - Cover4
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