Field Study on Actual Usage of Occupancy-Reactive Space Heating Control

Toru Yano,Shuichiro Imahara

doi:10.1109/access.2021.3067884

Abstract

We present evaluation of actual use of an occupancy-reactive space heating control, which changes set-point temperatures in space heating for energy-savings based on changes in occupancy state. We performed an experiment over two winter months in Lyon, France. In this experiment, occupants were provided with occupancy-reactive and pre-scheduled controls via a home energy management system (HEMS) and they were also allowed to control space heating manually via a thermostat or the HEMS. Occupants decided which control to use from among the two advanced controls and manual control, whereas control availability was limited in some experimental periods. To grasp actual usage of the two advanced controls, we introduce energy-saving potential for valve-regulated space heating and determine numbers of frequent users who applied any of the occupancy-reactive, the pre-scheduled or manual control. We also analyze actual energy consumption of space heating of the frequent users of each control. Our findings suggest energy-saving effects by the occupancy-reactive control, but the results show that the number of the occupancy-reactive control users in the experiment was not so large. This observation encourages reconsideration of the assumption that advanced controls such as the occupancy-reactive control are used fully by occupants in previous studies, indicating a necessity for promoting comprehension and active use of occupancy-reactive controls.

Highlights

The 2015 Paris Agreement calls for further reduction of greenhouse gases such as carbon dioxide [1], and the International Energy Agency has pointed out that improved energy efficiency is an important aspect of such reductions [2]
Space heating consumes a large portion of energy expenditure in cold regions such as Europe, with space heating in residential and non-residential areas accounting for 70% and 40% of total energy consumption, respectively, in the EU [3]
Occupancy-driven controls may be implemented through use of smart thermostats [25], [26] or home energy management systems (HEMS) [27], [28], whereas other HEMS functions include demand response [29], [30], energy equipment management [31], and energy feedback [32]

Summary

Introduction

The 2015 Paris Agreement calls for further reduction of greenhouse gases such as carbon dioxide [1], and the International Energy Agency has pointed out that improved energy efficiency is an important aspect of such reductions [2]. Occupancy-driven heating, ventilation, and airconditioning (HVAC) controls for energy-saving have been. The occupancy-driven HVAC controls can be categorized as occupancy-reactive controls [6], [10], [14], [16], [20], [21], [24] and occupancy-predictive controls [7]–[9], [11]–[13], [15], [17]–[19], [22], [23] The former is based on changes in occupancy state of a target space such as a room or house. The latter uses predictions of occupant arrival times in addition to changes in occupancy state. Occupancy-driven controls may be implemented through use of smart thermostats [25], [26] or home energy management systems (HEMS) [27], [28], whereas other HEMS functions include demand response [29], [30], energy equipment management [31], and energy feedback [32]

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