Gesche M. Huebner

The Potential for Energy Reduction in UK Commercial Offices Through Effective Management and Behaviour Change

General office equipment can be responsible for a significant proportion of overall electrical energy consumption in UK offices and this is predicted to rise significantly over the coming years [Webber, C. A., Roberson, J. A., Brown, R. E., Payne, C. T., Nordman, B., & Koomey, J. G. (2001). Field surveys of office equipment operating patterns. Berkley: CA: Lawrence Berkley National Laboratory]. As a significant contributor to overall energy use, this equipment has a corresponding cost and carbon impact. The legally binding requirements of the climate change act [Department of Energy and Climate Change. (2008). The climate change act. London: The Ministry of Justice] present a need to address the impact of office equipment, especially within the less-efficient existing building stock. In this study the range of energy consumption patterns observed across workstations in two typical UK, air-conditioned office spaces covering 90 desks and the potential effect of using feedback to encourage energy reduction through behaviour change are explored. The project monitored energy consumption over a four-month baseline period. Taking into account technical, behavioural and environmental influences this baseline established that a significant variation in consumption patterns exists between workstations providing the same function, in comparable locations and over the same period of time. Following the establishment of the baseline data further monitoring took place to assess the effect of behaviour change interventions through the provision of comparative feedback. The core driver behind the variation in consumption identified was found to be occupant behaviour over technical and environmental considerations. The study establishes that it is possible to reduce energy use, carbon emissions and cost associated with desk-level electricity consumption by up to 20% through behaviour change in typical UK office spaces. Further savings are possible through energy management and procurement policy, but behaviour change offers significant initial reductions for limited investment.

The shape of warmth: temperature profiles in living rooms

The most commonly used family of models in representing the UK building stock, BREDEM (the Building Research Establishment Domestic Energy Models), assume that all homes exhibit the same heating pattern and hence can be expected to have similar temperature profiles over the course of a day. The presented research shows that homes differ significantly in their respective temperature profile over the course of the day. A cluster analysis performed on temperature data from 275 living rooms in English homes over three winter months resulted in four different clusters of temperature profiles. The clusters differ significantly in their shape, as revealed by visual inspection, and supported by significant differences in minimum and maximum temperatures and temperature variability across the day. About 40% of homes showed a bimodal temperature pattern as assumed under BREDEM. However, the remaining 60% showed very different profiles. These findings challenge the assumption that one standard pattern fits all homes. Different temperature demand profiles have important implications for future peak power demands, particularly if domestic space heating is switched to electricity. It is also helpful for relating occupant demographics to appropriate forms of fabric retrofit.

Energy-saving occupant behaviours in offices: change strategies

ABSTRACT As regulated energy consumption in buildings is reduced, the proportional importance of unregulated energy consumption increases. Reducing unregulated energy use in the commercial office requires an understanding of the factors that influence workplace behaviour. To date these factors have been assumed to be similar to those that influence behaviour in the home. However, the social dynamics of the workplace are different to those in the home. This study examines the degree to which theories of behaviour change generated largely in a domestic building setting could be used as the basis for designing interventions to reduce unregulated energy consumption in the workplace. It studies the unregulated energy consumption of 39 workers engaged in office-type activities in two separate locations. Following a 100-day monitoring period, three behaviour change interventions were developed and their impact measured over a 100-day period. Results from the study found, on average, an 18.8% reduction in energy use was achieved. Furthermore, by comparing pre- and post-intervention responses to an environmental questionnaire, it was evident that savings were realized without significant changes to pro-environmental attitude or perceived social norms, which may have implications for energy-saving interventions in the commercial sector.

Drivers of diversity in human thermal perception – A review for holistic comfort models

ABSTRACT Understanding the drivers leading to individual differences in human thermal perception has become increasingly important, amongst other things due to challenges such as climate change and an ageing society. This review summarizes existing knowledge related to physiological, psychological, and context-related drivers of diversity in thermal perception. Furthermore, the current state of knowledge is discussed in terms of its applicability in thermal comfort models, by combining modelling approaches of the thermoneutral zone (TNZ) and adaptive thermal heat balance model (ATHB). In conclusion, the results of this review show the clear contribution of some physiological and psychological factors, such as body composition, metabolic rate, adaptation to certain thermal environments and perceived control, to differences in thermal perception. However, the role of other potential diversity-causing parameters, such as age and sex, remain uncertain. Further research is suggested, especially regarding the interaction of different diversity-driving factors with each other, both physiological and psychological, to help establishing a holistic picture.

Possible future impacts of elevated levels of atmospheric CO2 on human cognitive performance and on the design and operation of ventilation systems in buildings

This paper brings together a rapid evidence assessment of impacts of elevated CO2 concentrations on human cognition with IPCC projections of atmospheric CO2 concentration by the end of the present century, and an analysis of potential consequences of increased atmospheric CO2 concentrations for ventilation systems in buildings and other enclosed spaces. Whilst only limited research has been done on the effect of CO2 on cognition (as opposed to air quality in general), half of the studies reviewed indicate that human cognitive performance declines with increasing CO2 concentrations. Hence, given the likelihood of increasing atmospheric CO2 concentration by the end of the 21st century, direct impacts of anthropogenic CO2 emissions on human cognitive performance may be unavoidable. Attempts to minimise these direct impacts are likely to result in significant indirect impacts on the engineering of ventilation systems and associated energy use in all enclosed spaces including buildings and transport systems. Practical application : This paper concerns what may well be one of the most important long-term drivers of the design, management, operation and regulation of ventilation systems over the remainder of the 21st century. It will be relevant to professionals, particularly at senior levels in the building industry.

Comparison of indoor temperatures of homes with recommended temperatures and effects of disability and age: an observational, cross-sectional study

Objectives We examine if temperatures in winter in English homes meet the recommendation of being at least 18°C at all times. We analyse how many days meet this criterion and calculate the hours per day and night being at/above 18°C. These metrics are compared between households with occupants aged above 64 years or having a long-term disability (LTD) and those younger and without disability. Design Cross-sectional, observational. Setting England. Participants 635 households. Outcomes measures (1) Mean temperatures, (2) proportion of days of the measurement period meeting the criterion, (3) average hours at/above 18°C, (4) average hours at night at/above 18°C. Results Mean winter temperatures in the bedroom were MBR=18.15°C (SD=2.51), the living room MLR=18.90°C (SD=2.46) and the hallway MHall=18.25°C (SD=2.57). The median number of days meeting the criterion was 19–31%. For the living room, more days meet the criterion in the group with a LTD (Mdisability=342 vs Mno_disability=301, 95% CI 8 to 74), and with someone over 64 years present (Mabove64=341, Mbelow65=301 95%, CI 8 to 74). The median number of hours/day meeting the criterion was 13–17. In the living room, households with a disability had more hours at 18°C (Mdisability=364, Mno_disability=297, 95% CI 17 to 83) as did the older age group (Mabove64=347, Mbelow65=296, 95% CI 18 to 84). In the hallway, more hours met the criterion in households with a disability (Mdisability=338, Mno_disability=302, 95% CI 3 to 70). 247 homes had at least nine hours of at least 18°C at night; no effect of age or disability. Conclusions Many households are at risk of negative health outcomes because of temperatures below recommendations.