PrefaceThe Federal government is the largest single energy consumer in the United States; consumption approaches 1.5 quads/year of energy (1' quad = lo1' Btu) at a cost valued at nearly $10 billion annually. The U.S. Department of Energy (DOE) Federal Energy Management Program (FEMP) supports efforts to reduce energy use and associated expenses in the Federal sector. One such effort, the New Technology Demonstration Program (NTDP), seeks to evaluate new energy-saving U.S. technologies and secure their more timely adoption by the U.S. government.Pacific Northwest Laboratory (PNL)'") is one of four DOE national multiprogram laboratories that participate in the NTDP by providing technical expertise and equipment to evaluate new, energy-saving technologies being studied and evaluated under that program.This two-volume report describes a field evaluation that PNL conducted for DOE/FEMP and the U.S. Department of Defense (DoD) Strategic Environmental Research and Development Program (SERDP) to examine the performance of a candidate energy-saving technology-a gas-engine-driven heat pump. The unit was installed at a single residence at Fort Sam Houston, a U.S. Army base in San Antonio, Texas, and the performance was monitored under the NTDP. Participating in this effort under a Cooperative Research and Development Agreement (CRADA) were York International, the heat pump manufacturer; Gas Research Institute (GRI), the technology developer; City Public Service of San Antonio, the local utility; American Gas Cooling Center (AGCC); Fort Sam Houston; and PNL. The purpose of the Fort Sam Houston/Triathlon demonstration is to evaluate the performance and cost-effectiveness of the Triathlon gas heat pump (GHP) in the Federal sector. This is done by measuring the performance of the candidate unit and comparing it to the measured performance of conventional heating, ventilating, and air-conditioning (HVAC) systems currently in the residences at the base. The energy consumption, thermal measurements, and maintenance records will be primary elements in the life-cycle cost analysis'of potential savings from the candidate unit.The NTDP project at Fort Sam Houston (San Antonio, Texas) features a 3-ton gas-enginedriven heat pump. A single-cylinder, four-stroke, 5-hp engine fueled by natural gas drives the heat pump's compressor. A distinctive feature of the technology is an inherent load-matching capability. The heat pump can vary engine speed and blower fan speed, and thereby . dynamically control capacity to balance with thermal loads. This balance minimizes the need for cycling and reduces the associated thermal losses, fluctuations in room temperature and humidity, and equipment wear. The unit produces added heating capacity and improved supply-air temperatures through engine-waste heat recovery. The Triathlon GHP is manufactured by York International.. Three test houses at the Fort were used for the field comparison of the Triathlon against conventional residential HVAC systems. The houses were chosen to have identical structur...