Develop Proposal to Revise the Alternative Calculation Method (ACM) for 2005 Title 24 Update

Goal Statement:
This new task is developing a proposal to revise the Alternative Calculation Method (ACM) to include an overall metric for distribution system efficiency in the reporting requirements of the 2005 Title 24 Standards.

Results:
The ACM proposal is complete and has been accepted by the CEC.

The proposed heating, ventilation, and air conditioning (HVAC) Transport Efficiency metric is the ratio between the energy expended to transport heating, cooling, and ventilation throughout a building and the total thermal energy delivered to the various conditioned zones in the building. The transport energy includes all distribution-fan, ventilation-fan, and pump consumption [excluding domestic hot water (DHW) pumps], and the thermal energy delivered is the sum of all zone loads. This ratio can be calculated over the course of a year as well as under design conditions.

The proposal is simply a set of reporting changes, the goal of which is to provide feedback within the compliance process and thereby within the design process, on the fraction of HVAC energy use that is used for blowing and pumping thermal energy and ventilation air around a proposed building. All of the variables required to calculate the HVAC Transport Efficiency are available in the standard reports from DOE-2. The proposal does not require any modifications to the standard, to prescriptive or mandatory measures, or to the modeling algorithms in compliance software. Therefore, the ACM proposal should not precipitate significant efforts on the part of ACM providers.

We are continuing to work with Bill Pennington (CEC Project Manager, Energy Efficiency and Demand Analysis Division) on implementation issues related to the proposed ACM change.

Downloads and Links:

• ACM-Change Proposal for 2005 Title 24 Update (872 KB, 4 pp)
   
• CEC PIER-II contract (#500-98-026)

Contact: Craig Wray, Lawrence Berkeley National Laboratory (LBNL), (510) 486-4021