Design Guide: Making Homes Cool and Efficient
The California Residential New Construction HVAC Design Guide, produced by the consulting firm ConSol, was created to address these problems by consolidating the relevant information for the HVAC design process into an easy-to-use reference and training tool. The guide presents a start-to-finish breakdown of the HVAC design process and discusses how each step can help lead to an energy-efficient system.
The guide also highlights how some elements of HVAC system design fit into the overall construction process, and it discusses specific measures that can be used to reduce HVAC energy use in production homes. In addition, it identifies which personnel need to be involved with the different components of the HVAC design to ensure that it is energy efficient.
FEATURES AND BENEFITSThe design guide breaks down the HVAC design process into seven high-level steps to guide the development of an energy-efficient system including: determine zone, calculate room-by-room loads, select/size equipment, lay out duct system, determine operating conditions, size ducts, and apply final touches.
The guide also includes specific recommendations for special design topics, such as the following:
The guide also provides a table that lists HVAC, building design, and construction personnel and describes how they are affected by HVAC system design components. This was designed to make it easy to identify the key personnel who need to be involved with design decisions.
In addition, the guide provides a checklist of HVAC-related items to be discussed with stakeholders early in the design process. Example items for discussion include where to locate the condenser, refrigerant lines, ducts, and the thermostat.
APPLICATIONSThe California Residential New Construction HVAC Design Guide is written for HVAC designers, architects, and builders. It is particularly suited for production homes in California and areas with similar climates. The HVAC systems discussed in the guide are split or single-packaged air conditioners or heat pumps, with a cooling capacity of 5 tons or less, that are used in residential applications.
The guide highlights California building codes that are relevant to air conditioning design. For instance, the 2001 California Mechanical Code requires that all residential duct systems be sized according to the Air Conditioning Contractors of America (ACCA) Manual D, which requires ACCA Manual J. According to the California Energy Commission (CEC), an update is scheduled for this code at the end of 2006, which may alter the Manual D requirement so that it applies only to homes needing outdoor air.
Also, the 2001 Residential Manual of Title 24 dictates how heat loss and gain calculations are to be performed and establishes the temperatures to be used for sizing equipment. The 2005 Residential Manual, which went into effect Oct. 1, 2005, changes the design temperatures to be used and also offers an alternate sizing method. ConSol said it will update the guide as these codes or other changes dictate.
ConSol said it would use the design guide to train builders, planners, and others involved with production homes. Although the California Mechanical Code requires the use of ACCA Manual D, many jurisdictions are unaware of this requirement, and it is often not enforced, said the CEC. By educating production-home builders and others, this guide should help to ensure compliance with the code, according to the CEC.
This project was conducted by the California Energy Commission's Public Interest Energy Research (PIER) program. PIER said it supports public-interest energy research and development designed "to help improve the quality of life in California by bringing environmentally safe, affordable, and reliable energy services and products to the marketplace."
The Building Industry Institute, ConSol, and Fluent Inc. collaborated on this guide project. Detailed reports on this project can be downloaded at www.energy.ca.gov/pier/final_project_reports/CEC-500-2005-118.html. To view technical briefs on other topics, visit www.esource.com/public/products/cec_form.asp. For more concerning the guide, contact Rob Hammon at ConSol, 209-473-5000 or email@example.com; or contact Martha Brook at California Energy Commission, 916-654-4086 or firstname.lastname@example.org.
Publication date: 08/07/2006