HVAC Energy Efficiency Maintenance Study

Description 

Research has shown that the performance of existing residential and small-commercial heating ventilating and air-conditioning (HVAC) systems is far from optimal. In many cases, the systems were never installed correctly and have never operated optimally, resulting in lower efficiency than implied by the nameplate rating. In other cases, the performance has degraded over time, either because of faults or improper service, causing the equipment to malfunction or to perform poorly. Measures such as duct sealing and repair, condenser and evaporator coil cleaning, refrigerant charge and air flow adjustments, economizer retro-commissioning, and HVAC controls can potentially produce significant savings. 

The California investor-owned utilities (IOUs) have shown a great deal of leadership in initiating maintenance-based HVAC programs. These and other energy efficiency programs have been in existence since the 1980s, and have reached millions of homes and small businesses. Despite their success in reaching the market, however, the energy savings attributable to HVAC maintenance programs have been called into question. For example, one evaluation of savings for residential charge and air-flow adjustment programs in the 2006-2008 program cycle found quite low savings rates, but also found wide variations in the different program impact parameters. These studies raised the possibility that some of the Evaluation, Measurement and Verification (EM&V) questions being asked and answered have such large uncertainties that conclusions and recommendations based on them should be considered carefully. 

In the long run, achieving the ambitious California Public Utilities Commission (CPUC) “BigBold” HVAC goal of 50% improvement in residential and small commercial HVAC system efficiency will require new, more comprehensive programs that have the potential for greater impact. For these programs to constitute a prudent use of ratepayer money, however, they must be designed based on a good understanding of the impacts and interrelationships of individual and combined system faults (i.e., abnormal conditions that may lead to system performance degradation or failure) and maintenance measures. A simple “widgets” approach that focuses on individual measures that save 10% here and 5% there will not achieve the level of savings that is needed to meet the CPUC’s ambitious goal. HVAC technologies should benefit from a broad based systems approach. 

Highlights of our analysis include the following key observations, each of which is discussed in depth in the report.

Table of Contents :-
Executive Summary

1. Introduction
2. Project Objectives
3. Methodology
4. Refrigeration Cycle Analysis and RCA Programs
5. Duct Systems and DTS Programs
6. EER, Energy Savings, and Peak Demand Reduction
7. Uncertainties in Site Measurements
8. Uncertainties in kWh Calculations
9. Other Uncertainties
10. Implications of Uncertainty
11. Roadmap to CPUC Goals
12. Research Plan
13. Conclusions and Recommendations
14. References 

Glossary.

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