Tuesday, June 27, 2017: 9:45 AM-10:45 AM
Fundamentals and Applications
Chair:
Daniel Pettway, Hobbs & Associates
This session covers a breadth of research for HVAC applications including fault conditions as handled by building automation systems, air leakage in buildings and revised weather data.
1 Updating the ASHRAE Climate Design Data for 2017 (RP-1699) (LB-17-007)
Under ASHRAE Research Project 1699 (RP-1699) we provide an update of the data used both in the “Climatic Design Information” chapter of the 2017 ASHRAE Handbook of Fundamentals and in ANSI/ASHRAE Standard 169, “Weather Data for Building Design Standards”. A total of 8118 stations were successfully processed worldwide representing a 26% increase compared to 2013. Reported elements now include monthly average wind speed, wet bulb temperature return periods and monthly-average daily all-sky global horizontal solar radiation. A number of pre-screening and post-processing tools were developed in order to ensure a reliable and useful product.
2 Effects of Air Leakage on Buildings’ Overall Thermal Resistances Based on U.S. Climate Zones (LB-17-008)
Air-leakage through building envelopes causes significant energy losses. Air-tightness codes do not account for air-leakage due to wind-driven pressure gradients and thermal resistance codes do not consider any air-leakage effects. Air-leakage needs to be included codes to understand the effects on thermal performance. We calculated effective thermal resistances in 103 locations considering air-leakage effects, to see effects on thermal performance. Simulations showed decreased thermal resistances and increased energy losses in every climate. Varying levels of thermal performance demonstrate relative importance of air-tightness in different climates. Results imply current codes do not accurately represent thermal performance and where air-tightness matters most.
3 Automatic Fault Detection and Diagnostics and Hierarchical Fault Suppression in ASHRAE (RP-1455) (LB-17-009)
This paper describes two of the unique elements of the advanced control sequences developed for ASHRAE Research Project 1455 (RP-1455): automatic fault detection and diagnostics (AFDD) and hierarchical alarm suppression. AFDD is a method used to identify fault conditions and provide possible diagnoses. Hierarchical fault suppression is a method based on hierarchical structure used to reduce the incidence of nuisance alarms. It is written by the members of the research team and is part of the deliverables for this research project. AFDD and hierarchical alarm suppression will further enhance the ability of DDC systems to make intelligent alarm distribution and management decisions.