Engineering Papers⌕ Search

Engineering topics

Walker, Iain

Publications and source records attributed to Walker, Iain.

41 records · Page 3
All sourcesNASA NTRSDOE OSTI
DOE OSTI2014

Development of an Outdoor Temperature-Based Control Algorithm for Residential Mechanical Ventilation Control

Smart ventilation systems use controls to ventilate more during those periods that provide either an energy or IAQ advantage (or both) and less during periods that provide a dis advantage. Using detailed building simulations, this study addresses one of the simplest and lowest cost types of smart controllers —outdoor temperature- based control. If the outdoor temperature falls below a certain cut- off, the fan is simply turned off. T he main principle of smart ventilation used in this study is to shift ventilation from time periods with large indoor -outdoor temperature differences, to periods where these differences are smaller, and their energy impacts are expected to be less. Energy and IAQ performance are assessed relative to a base case of a continuously operated ventilation fan sized to comply with ASHRAE 62.2-2013 whole house ventilation requirements. In order to satisfy 62.2-2013, annual pollutant exposure must be equivalent between the temperature controlled and continuous fan cases. This requires ventilation to be greater than 62.2 requirements when the ventilation system operates. This is achieved by increasing the mechanical ventilation system air flow rates.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2014

A Meta-Analysis of Single-Family Deep Energy Retrofit Performance in the U.S.

The current state of Deep Energy Retrofit (DER) performance in the U.S. has been assessed in 116 homes in the United States (US), using actual and simulated data gathered from the available domestic literature. Substantial airtightness reductions averaging 63% (n=48) were reported (two- to three-times more than in conventional retrofits), with average post-retrofit airtightness of 4.7 Air Changes per House at 50 Pascal (ACH 50 ) (n=94). Yet, mechanical ventilation was not installed consistently. In order to avoid indoor air quality (IAQ) issues, all future DERs should comply with ASHRAE 62.2-2013 requirements or equivalent. Projects generally achieved good energy results, with average annual net-site and net-source energy savings of 47%±20% and 45%±24% (n=57 and n=35), respectively, and carbon emission reductions of 47%±22% (n=23). Net-energy reductions did not vary reliably with house age, airtightness, or reported project costs, but pre-retrofit energy usage was correlated with total reductions (MMBtu). Annual energy costs were reduced $\$1,283$ ± $\$804$ (n=31), from a pre-retrofit average of $\$2,738$ ± $\$1,065$ to $\$1,588$ ± $\$561$ post-retrofit (n=25 and n=39). The average reported incremental project cost was $\$40,420$ ± $\$30,358$ (n=59). When financed on a 30-year term, the median change in net-homeownership cost was only $\$1.00$ per month, ranging from $\$149$ in savings to an increase of $\$212$ (mean= $\$15.67$ ± $\$87.74$; n=28), and almost half of the projects resulted in reductions in net-cost. The economic value of a DER may be much greater than is suggested by these net-costs, because DERs entail substantial non-energy benefits (NEBs), and retrofit measures may add value to a home at resale similarly to general remodeling, PV panel installation, and green/energy efficient home labels. These results provide estimates of the potential of DERs to address energy use in existing homes across climate zones that can be used in future estimates of the technical potential to reduce household energy use and greenhouse gas emissions through DERs.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2014

Duct Leakage Repeatability Testing

Duct leakage often needs to be measured to demonstrate compliance with requirements or to determine energy or Indoor Air Quality (IAQ) impacts. Testing is often done using standards such as ASTM E1554 (ASTM 2013) or California Title 24 (California Energy Commission 2013 & 2013b), but there are several choices of methods available within the accepted standards. Determining which method to use or not use requires an evaluation of those methods in the context of the particular needs. Three factors that are important considerations are the cost of the measurement, the accuracy of the measurement and the repeatability of the measurement. The purpose of this report is to evaluate the repeatability of the three most significant measurement techniques using data from the literature and recently obtained field data. We will also briefly discuss the first two factors. The main question to be answered by this study is to determine if differences in the repeatability of these tests methods is sufficient to indicate that any of these methods is so poor that it should be excluded from consideration as an allowed procedure in codes and standards.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2013

Berkeley Lab Answers Your Home Energy Efficiency Questions

In this follow-up "Ask Berkeley Lab" video, energy efficiency expert Iain Walker answers some of your questions about home energy efficiency. How do you monitor which appliances use the most energy? Should you replace your old windows? Are photovoltaic systems worth the cost? What to do about a leaky house? And what's the single biggest energy user in your home? Watch the video to get the answers to these and more questions.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗