Characterizing Variations in the Indoor Temperature and Humidity of Guest Rooms with an Occupancy-Based Climate Control Technology

Hyojin Kim,Emily Oldham

doi:10.3390/en13071575

Abstract

This paper characterizes variations in the indoor temperature and humidity profiles of actual guest rooms equipped with Occupancy-Based Climate Control (OBCC) systems that were used to initiate a temperature setback to 15.6 °C in the winter and to 26.7 °C in the summer in the guest rooms. Empirical knowledge of these conditions can provide useful insights for an improved field demonstration and optimization of OBCC, as well as for a more realistic temperature and occupancy input for building simulations for hotel guest rooms. As a result, one year of one minute temperatures and humidity data was characterized against outdoor climate for three different occupancy modes, which was useful to identify the observed room-to-room variations in heat losses and resultant indoor temperatures during the heating season due to the different dynamic heat balance conditions of the guest rooms. This indicated potential discomfort in the rooms that appeared to have a stronger association between outdoor and indoor temperatures, which was also identified from the thermal comfort survey indicating thermostat-related discomfort sources. Interestingly enough, the guests who stayed in these rooms tended to set their thermostat at higher setpoint temperatures when they occupied the room, which appeared to compensate for the low balance-point temperatures of these rooms.

Highlights

According to the U.S Energy Information Administration’s (EIA) Commercial Buildings EnergyConsumption Survey (CBECS), hotel buildings are considered part of the lodging sector
One year temperature and humidity of actual guest rooms equipped with Occupancy-Based Climate Control (OBCC) systems across different seasons
The measured indoor temperatures and humidity data were characterized using the binned box-and-whisker plots for three different occupancy modes against outdoor temperatures binned into 5 ◦ C (9 ◦ F) bins

Summary

Introduction

Consumption Survey (CBECS), hotel buildings are considered part of the lodging sector. Of total building energy use in the U.S, about 8.1% was consumed by the lodging sector as reported by the. 2012 CBECS [1], which made the lodging sector the fifth-largest energy consumer. To save energy in hotel guest rooms, recent industry efforts have focused on Occupancy-Based Climate Control (OBCC). Technology using either occupancy sensors or card-key based control systems that activate temperature setback schedules when the hotel guest rooms are vacated. Hotel guest rooms are considered to be one of the most appropriate building types for OBCC due to their relatively low occupancy rates and unpredictable occupancy schedules [2]. The use of occupancy sensors to control thermal conditions of unoccupied guest rooms in hotels was discussed in an early study by Fountain et al [5]. The latest edition of American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) Standard 90.1-2016 [6], which has Energies 2020, 13, 1575; doi:10.3390/en13071575 www.mdpi.com/journal/energies

Methods

Results

Discussion

Conclusion