DEVELOPMENT OF A REFRIGERANT DISTRIBUTION SECTION FOR ASHRAE STANDARD 152.

Andrews, J. W.

Brookhaven National Laboratory

关键词: Efficiency;    Heating;    Testing;    Refrigerants;    Computers;   

DOI  :  10.2172/786621
RP-ID  :  BNL--68604
RP-ID  :  AC02-98CH10886
RP-ID  :  786621

美国|英语

来源: UNT Digital Library

【 摘 要 】

In a recent draft report titled ''Impacts of Refrigerant Line Length on System Efficiency in Residential Heating and Cooling Systems Using Refrigerant Distribution,'' (Andrews 2000) some baseline calculations were performed to estimate various impacts on system efficiency of long refrigerant distribution lines. Refrigerant distribution refers to ''mini-splits'' and other types of space beating and cooling equipment that utilize refrigerant lines, rather than ducts or pipes, to transport heat and cooling effect from the outdoor unit to the building spaces where this heat or cooling is used. Five factors affecting efficiency were studied in each of the space conditioning modes (heating and cooling) for a total of ten factors in all. Temperature changes and pressure drops in each of the two refrigerant lines accounted for four of the factors, with the remaining one being elevation of the indoor unit relative to the outdoor unit. Of these factors, pressure drops in the suction line in cooling showed by far the largest effect. This report builds on these baseline calculations to develop a possible algorithm for a refrigerant distribution section of ASHRAE Standard 152. It is based on the approximate treatment of the previous report, and is therefore subject to error that might be corrected using a more detailed analysis, possibly including computer modeling and field testing. However, because the calculated efficiency impacts are generally small (a few percent being typical) it may be that the approximate treatment is sufficient. That question is left open for discussion. The purpose of this report is not to advocate the adoption of the methodology developed, but rather to present it as an option that could either be adopted as-is or used as a starting point for further analysis. It is assumed that the reader has available and is familiar with ASHRAE Standard 152P and with the previous analysis referred to above.