The Greenbuilt house, is an all-electric, 1980's era home in the eastern Sacramento suburb of Fair Oaks that was retrofit by Greenbuilt Construction as part of Sacramento Municipal Utility District's (SMUD) Energy Efficient Remodel Demonstration (EERD) Program. The project was a joint effort between the design-build team at Greenbuilt Construction, led by Jim Bayless, SMUD and their project manager Mike Keesee, and the National Renewable Energy Laboratory (NREL). The goal of the Energy Efficient Remodel Demonstration program is to work with local builders to renovate homes with cost-effective energy efficient retrofit measures. The homes remodeled under the EERD program are intended to showcase energy efficient retrofit options for homeowners and other builders. The Greenbuilt house is one of five EERD projects that NREL has supported. NREL's main role in these projects is to provide energy analysis and to monitor the home's performance after the retrofit to verify that the energy consumption is in line with the modeling predictions. NREL also performed detailed monitoring on the more innovative equipment included in these remodels, such as an add-on heat pump water heater.

Building energy simulations can be used to predict a building's interior conditions, along with the energy use associated with keeping these conditions comfortable. These models simulate the loads on the building (e.g., internal gains, envelope heat transfer), determine the operation of the space conditioning equipment, and then calculate the building's temperature and humidity throughout the year. The indoor temperature and humidity are affected not only by the loads and the space conditioning equipment, but also by the capacitance of the building materials, which buffer changes in temperature and humidity. This research developed an empirical method to extract whole-house model inputs for use with a more accurate moisture capacitance model (the effective moisture penetration depth model). The experimental approach was to subject the materials in the house to a square-wave relative humidity profile, measure all of the moisture transfer terms (e.g., infiltration, air conditioner condensate) and calculate the only unmeasured term: the moisture absorption into the materials. After validating the method with laboratory measurements, we performed the tests in a field house. A least-squares fit of an analytical solution to the measured moisture absorption curves was used to determine the three independent model parameters representing the moisture buffering potential of this house and its furnishings. Follow on tests with realistic latent and sensible loads showed good agreement with the derived parameters, especially compared to the commonly-used effective capacitance approach. These results show that the EMPD model, once the inputs are known, is an accurate moisture buffering model.

This document describes a simple and general way to generate House Simulation Protocol (HSP)-consistent internal sensible and latent loads in unoccupied homes. It is newly updated based on recent experience, and provides instructions on how to calculate and set up the operational profiles in unoccupied homes. The document is split into two sections: how to calculate the internal load magnitude and schedule, and then what tools and methods should be used to generate those internal loads to achieve research goals.

The report provides a detailed method for accurately measuring and monitoring performance of a residential Mini-Split Heat Pump. It will be used in high-performance retrofit applications, and as part of DOE's Building America residential research program.

ft2. The design heating loads in the homes were so small that each home is heated with a single, sealed-combustion, natural gas room heater. The cost savings from the simple HVAC systems made possible the tremendous investments in the homes' envelopes. The Consortium for Advanced Residential Buildings (CARB) monitored temperatures and comfort in several homes during the winter of 2009-2010. In the Spring of 2011, CARB obtained utility bill information from 13 occupied homes. Because of efficient lights, appliances, and conscientious home occupants, the energy generated by the solar electric systems exceeded the electric energy used in most homes. Most homes, in fact, had a net credit from the electric utility over the course of a year. On the natural gas side, total gas costs averaged $377 per year (for heating, water heating, cooking, and clothes drying). Total energy costs were even less - $337 per year, including all utility fees. The highest annual energy bill for any home evaluated was $458; the lowest was $171.

Two modular office units were tested at the National Renewable Energy Laboratory (NREL) to establish each unit's thermal performance. The two units were nearly identical in appearance, but one was built with structural insulating panels (SIP), and the other was built using standard frame construction. The primary objective of these tests was to compare the thermal performance of buildings using SIP and standard frame construction. Both units were tested under carefully controlled steady-state conditions in the NREL large-scale environmental enclosure. They were then moved outdoors where Short-Term Energy Monitoring (STEM) tests were performed, and long-term heating and cooling energy use was measured. A secondary objective was to evaluate the accuracy of the NREL STEM method by comparing the results of outdoor STEM tests to steady-state indoor test results. STEM is a method developed by NREL to determine key thermal parameters of a building in-situ, based on a 3-day test sequence. The indoor test facility also provided the opportunity to investigate the phenomenon of infiltration heat recovery in a real building, under carefully controlled conditions, to evaluate the stability of the concentration decay method of tracer gas-based infiltration monitoring, and to compare the blower-door method with the tracer-gas technique in determining infiltration.This project was a cooperative effort with the Structural Insulated Panel Association, the Modular Building Institute, All-American Modular (AAM, the manufacturer of the units), and GE Capitol (the owner of the units). Richard Harmon, the president of AAM, requested NREL's assistance in exploring the feasibility of converting his manufacturing process to SIP construction. His engineering staff needed to assess which comfort and energy benefits might be associated with this new technology. AAM manufactured the two units, and NREL tested the modules for 8 months.

A residential building in Tucson, Arizona, was studied to evaluate opportunities for reducing cooling energy use in a hot dry climate. The reduction of solar heat gain was strongly influenced by spectrally selective windows, architectural shading, and site shading from adjacent buildings. The study emphasized accurately modeling these features to account for effects on the energy load. Building performance was modeled using a detailed hourly energy simulation tool and was measured while unoccupied for a period of 12 days. Model inputs included direct measurements of the net air exchange rate, surface reflectance, and window transmittance. Model results showed good agreement with the direct measurements of cooling loads and air-conditioning energy use. A parametric study of annual energy use is presented showing the impacts of glazing type, architectural shading, site shading, and building orientation. It is important to understand these interactions to optimize energy savings in community-scale housing developments.

In December of 1996, heat pipe heat exchangers were installed on three air handlers at Hangar L at the Cape Canaveral Air Station, Kennedy Space Center, Cape Canaveral, Florida. These retrofits were implemented with the intent to improve the dehumidification performance of the cooling systems, reduce the electric and steam energy required for reheating air, and reduce electric energy used by the chillers. Audits were conducted before and after the heat pipes were installed and a detailed monitoring system was set up to record hourly operating conditions of each of the three air-handling units. The audit information and monitored data were used to create a simulation model of the three air-handling systems and annual energy savings were predicted. Energy savings for air handling unit 1 (AHU-1) were found to be negligible. Heat pipe installation in AHU-1 may have been inappropriate because of the design of the original cooling coils. Annual savings for AHU-2 are small, primarily because the required reheat for the system was already small. AHU-3 was the best application for the heat pipes and showed savings of 70,000 kWh per year. Interior humidity conditions improved after installation of the heat pipes for AHU-2 and AHU-3.