Residential geothermal air-conditioning: inhabitants’ comfort, behaviour and energy use

How do occupants’ behaviour and expectations influence energy use for residential geothermal air-conditioning? This detailed study of 40 homes with geothermal AC in Sydney, Australia, during the period 2019–20 covers one of hottest Australian summers and increased daytime occupancy over the winter due to working from home during Covid-19 lockdowns. Monitored data are analysed for ground source heat pump (GSHP)-AC energy, occupancy, indoor conditions, as well as a snapshot resident feedback captured during hot and cold spells. Findings indicate that the homes built to comply with 2011 energy efficiency standards maintain indoor temperatures within 10–12°C of peak summer and minimum winter temperatures, without AC. A general preference to adopt adaptive strategies such as ceiling fans and appropriate clothing before deploying AC is evident for moderately hot and cold days. A heightened dependence on AC is seen for extreme days. However, a significant number of houses adhere to a narrow range of acceptable temperatures, thereby increasing the take-up of GSHP-AC and energy consumption. The replacement of conventional AC with alternate technologies is not a one-stop solution in, and of, itself. There is a need for improved building low energy design and construction based on a better understanding of occupant behaviour and energy consequences. POLICY RELEVANCE Although geothermal systems offer potential energy savings (especially in extreme conditions) and their potential for seamless technological replacement of conventional AC in homes, the findings suggest GSHP-AC is not a one-stop solution to reduce dependence on AC. The study reveals that the unconstrained use of GSHP-AC can increase energy consumption and squander energy savings achieved through its technological efficiency. The ‘conditioned’ expectations of inhabitants, stimulated by a lower tolerance of ‘imperfect’ conditions and availability of heating and cooling on standby, can lead to increased dependence and usage. In an increasing warming world, more stringent guidelines are needed for thermal performance and design to mitigate residual discomfort and transform occupant practices. These must also be supported with occupant education and engagement to ensure the design intent is realised. © 2022 The Author(s).

Assessment of Social Housing Energy and Thermal Performance in Relation to Occupants' Behaviour and COVID-19 Influence-A Case Study in the Basque Country, Spain

Evidence shows that people have a major impact on building performance. Occupants' impact is especially important in social housing, where their occupants may present greater vulnerabilities, and their needs are not always considered. This study aims to analyse the socio-demographic influence in social rental housing concerning hygrothermal comfort and energy consumption in a case study located in Vitoria, Spain during the first 4-month period of 2020 and 2021 (during and after COVID-19 lockdown). An innovative data management system is included, where the users and administration can see in real-time the temperature and consumption in the dwellings. A 2-phase method has been applied;phase 1 is associated with outdoor climate conditions, building properties and social profile. Phase 2 determined the results in energy consumption, indoor hygrothermal comfort and occupant energy-use pattern. The results show that the comfort levels and energy consumption vary according to the analysed social profiles, as well as the heating activation periods and domestic hot water system usage. In conclusion, socio-demographic characteristics of social housing households influence the hygrothermal comfort of their dwellings, occupants' behaviour and heating and domestic hot water energy consumption.

Assessment of Social Housing Energy and Thermal Performance in Relation to Occupants’ Behaviour and COVID-19 Influence—A Case Study in the Basque Country, Spain

Evidence shows that people have a major impact on building performance. Occupants’ impact is especially important in social housing, where their occupants may present greater vulnerabilities, and their needs are not always considered. This study aims to analyse the socio-demographic influence in social rental housing concerning hygrothermal comfort and energy consumption in a case study located in Vitoria, Spain during the first 4-month period of 2020 and 2021 (during and after COVID-19 lockdown). An innovative data management system is included, where the users and administration can see in real-time the temperature and consumption in the dwellings. A 2-phase method has been applied;phase 1 is associated with outdoor climate conditions, building properties and social profile. Phase 2 determined the results in energy consumption, indoor hygrothermal comfort and occupant energy-use pattern. The results show that the comfort levels and energy consumption vary according to the analysed social profiles, as well as the heating activation periods and domestic hot water system usage. In conclusion, socio-demographic characteristics of social housing households influence the hygrothermal comfort of their dwellings, occupants’ behaviour and heating and domestic hot water energy consumption.

A critical review on occupant behaviour modelling for building performance simulation of naturally ventilated school buildings and potential changes due to the COVID-19 pandemic

Occupant behaviour (OB) is one of the main causes of the energy performance gap between buildings’ performance prediction versus reality, since, due to its uncertainty and unpredictability, it is often oversimplified in the building performance simulation (BPS). Hence, previous studies developed OB models, mainly in the residential and office contexts, in order to predict and represent human behaviour in BPS. Yet, school buildings are different from other typologies due to contextual factors (e.g., occupants’ age, different daily timetables and group rules) and are in a unique position to promote energy efficiency for tomorrow’s citizens. Assessing OB in schools can lead to an improvement of the indoor environment, especially in naturally ventilated buildings, where window operation behaviour directly impacts on the air change rates and, consequently, on the indoor air quality. This study addresses the knowledge gap on OB modelling for naturally ventilated (NV) and mixed-mode (MM) school buildings. The reviewed papers were organized in three main themes, namely (i) OB models for BPS of NV and MM buildings, (ii) OB research studies in NV and MM school buildings and (iii) potential changes on OB in school buildings due to the COVID-19 pandemic. The analysis focused on three phases of the OB modelling framework: data collection (pre-processing), model development (processing) and model implementation (post-processing). Important research gaps are identified, such as the reduced number of studies that cover the three phases of the modelling framework within the school buildings context and the need to better investigate the teachers’ behaviour and collective actions as important OB drivers in classrooms. Future research topics are also identified, such as which are the potential changes on actions’ drivers due to the COVID-19 pandemic in NV classrooms and to what extent they will be durable or ephemeral.

New Insights on the Energy Impacts of Telework in Canada.

Quantifying the energy impact of teleworking has been challenging because of the low prevalence of telework. The coronavirus disease 2019 pandemic and the associated widespread shift to telework provides a new opportunity to study the energy impact of teleworking. Within two months of the lockdowns, we surveyed 278 knowledge-based workers in Canada who started working primarily from home to investigate their energy-related behaviours and attitudes. The survey's major themes are energy-saving actions taken in the office, equipment used for telework, impacts on home energy usage, and both awareness of and response to electricity pricing. Given trends toward increased teleworking in the future, these results can inform public policy related to teleworking and energy.

Quantifier l'impact du télétravail sur la consommation d'énergie a longtemps été difficile en raison du faible recours au télétravail. La pandémie de la COVID-19 et le passage généralisé au télétravail fournit une nouvelle occasion pour étudier l'impact du télétravail sur la consommation d'énergie. Dans les deux mois qui ont suivi les confinements, nous avons interrogé 278 travailleurs ayant des emplois fondés sur le savoir qui ont commencé à travailler principalement de chez eux, afin d'étudier leurs comportements et attitudes quant à la consommation d'énergie. Les thèmes principaux de l'enquête sont les actions prises au travail visant la réduction de consommation d'énergie, l'équipement utilisé pour le télétravail, l'impact sur la consommation résidentielle, et la prise de conscience et la réaction quant au prix de l'électricité. Étant donné la tendance plus accrue au télétravail à l'avenir, ces résultats peuvent éclairer la politique publique en matière de télétravail et d'énergie.