Update to office equipment diversity and load factors (ASHRAE 1742-RP)

Abstract

The current article gives an overview of methods used for the determination of updated recommended diversity factors for various office equipment. The update to the diversity factors was required because of the introduction of new types of office equipment, such as laptop docking stations, and both increased equipment performance as well as improved power management. The present study, in particular, investigates the effects of the number of tested pieces of equipment as well as the interval duration for data reduction. Analysis and results on the effect of the different number of tested pieces of equipment and averaging intervals on the diversity factor are presented. Load factors for various office types are calculated using heat gain and diversity factor values of various office equipment. These updated office load factor values are included in the 2017 edition of the ASHRAE Fundamentals Handbook are found to be 10% to 33% lower than those published in the previous ASHRAE Fundamentals Handbook (2013). The article also presents recommendations for minimum equipment count required to determine diversity factors for various office equipment in a typical office space. For most tested equipment, 8 to 9 pieces of equipment tested in parallel appears to give acceptable results, for example, ±6% of the predicted value for diversity factor within the predicted 95% confidence interval.