Project Report


Enhancing the Performance of HVAC and
Distribution Systems-Residential New Construction

Paper presented at ACEEE 1992 Summer Study on Energy Efficiency in Buildings
Paper dated: 1992
Prepared by Proctor Engineering Group
Contributors: John Proctor with Jeff Hammarlund, George Cast and Tony Ward

Abstract

Field studies and field based modeling has shown the significant opportunities for electricity savings and peak demand reduction from repair of residential air conditioners, heat pumps, and their distribution systems. A few utility programs are being built to capture this potential on existing single family buildings.

This paper presents new data on the potential benefits of changing the common installation practice of both heat pumps and their distribution systems on new single and multi family dwellings.

Sixty six multi family and twelve single family buildings in the Los Angeles area were tested for distribution system leakage, air flow through the inside coil, and proper refrigerant charge. In spite of the fact that all the buildings were newly constructed, major problems were widespread in all three areas. These deficiencies and their frequency of occurance is reported.

The paper also describes how this information is being used to design and implement a utility sponsored residential new construction program. Major barriers to better design and installation of HVAC systems are identified and program stratigies to address these barriers are evaluated.

Methodology

The completed forms were reviewed by the LADWP program manager to determine that the proper work had been done. If the review determined that the unit needed to be retested, a return trip was made to complete the assignment.

The testing methodology is similar to that detailed in Proctor (1991). The house or apartment was pressurized by a blower door. Leakage from the duct system to outside the pressurized portion of the structure was then measured using a flow hood.

Departures from the methodology detailed in Proctor (1991) are:

  1. Duct leakage estimate is adjusted to the actual pressures present in the ducts during operation.
  2. The leakage was determined for the supply and return systems separately. Refrigerant charge was tested by superheat on capillary tube systems, and subcooling on thermostatic expansion valve systems.

Results

Most of the units investigated had significant problems with the distribution system and/or heat pump. New construction is not a guarantee that either the duct system or the heating/cooling appliance will perform to its design specifications. The problems and their probable effect on energy use vary between the multifamily sector and the single family sector. The results are presented in two sections. The first section details the results applicable to single family sites, the second applies to multifamily sites.

Also see Energy Efficiency Research

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