• Energy Research
• 11. Sustainability close

Abstract Night cooling strategies are gaining popularity with the raise in profile of Green Buildings and Sustainable rating systems. The use of night ventilation to exploit lower diurnal temperatures to pre-cool the building structure in preparation for the following day's gains is well known; however, the role which the facade has to contribute to night ventilation is not fully understood. Researchers are familiar with economiser cycles operation for central air conditioning systems and the ability of these to operate in night ventilation mode with simple modifications to the control strategy requires validation. Simulations were carried out for a typical office building in Adelaide to demonstrate that a traditional economiser cycle operating 24 h each day under thermostatic control delivers energy savings. A number of facade structures were considered and the effect of varying the location of the thermal mass within the structure was investigated. The paper gives details on the model used for the simulations and discusses the results obtained. It was found that increasing the mass on the inside of the facade is preferred over the external for the warm marine climate zone of Adelaide, South Australia.

The rating of buildings using thermal models represents a contrasting regulatory approach to prescriptive measures to improve the energy efficiency of buildings. This paper investigates the relationship between measured household energy use for thermal comfort purposes and the modelled thermal energy calculated under the Nationwide House Energy Rating Scheme (NatHERS), which is used for the regulation of minimum energy performance standards for new housing in Australia. Two different sets of housing in Adelaide, South Australia which were built a decade apart and to significantly different energy performance standards represent the basis of this study. The results show that better insulated houses represented by higher stars under the NatHERS scheme do use less energy for heating and cooling.

Thermally activated building systems (TABS) can work as thermal energy storage (TES) systems, which are useful in shifting the energy use of space cooling and heating in buildings. The present study analyses and optimizes simple deterministic control concepts for radiant wall supplied by a heat pump for cooling purposes. First, the "solar" concept was studied, which was focused on exploiting the output of a photovoltaic (PV) array. Secondly, a "peak load shifting" concept exploiting the low electricity cost and high heat pump energy efficiency during night periods was evaluated. The results showed that the "solar" concept saved between 57% and 95% in comparison to a conventional control in different PV installed capacities. Moreover, the optimized "peak load shifting" concept had lower operation cost than the conventional control with most of the PV configurations proposed. Therefore, the study showed that the investment in the PV array was fully harnessed only with specific controls. Furthermore, the "solar" control concepts were found to help achieving the goals of net-zero energy buildings by maximising self-consumption of renewable energies in the building, as well as reducing the total imported/exported energy. The authors acknowledge the South Australian Department of State Development who have funded this research through the Premier’s Research Industry Fund – International Research Grant Program (IRGP 33). The work was partially funded by the Spanish government (ENE2015-64117-C5-1-R (MINECO/FEDER), ENE2015-64117-C5-3-R (MINECO/FEDER), and ULLE10-4E-1305). GREA is certified agent TECNIO in the category of technology developers from the Government of Catalonia. The project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 712949 (TECNIOspring PLUS) and from the Agency for Business Competitiveness of the Government of Catalonia. The authors would like to thank the Catalan Government for the quality accreditation given to their research group (2017 SGR 1537) and the city hall of Puigverd de Lleida.

Abstract Climate change has been shown to significantly alter the heating and cooling needed to maintain thermal comfort within a home. However, limited studies have investigated the impact on the design philosophy associated with achieving an energy efficient building envelope with the onset of climate change. Applying robust future TMY for 2070 the change in heating and cooling demand has been studied in this paper for various combinations of external and internal wall insulation, roof insulation, reflective foil, thermally reflective roofs and different floor coverings. A building thermal model was used for the mild temperate climate of Adelaide, Australia, which requires both heating and cooling, but is dominated by heating. Climate change was found to increase and shift this demand to cooling dominated. It was determined that with climate change, heating becomes significantly less important in better insulated buildings and therefore measures which reduce cooling load are more critical. It is concluded that in this climate zone, climate change design approaches need to dramatically change to focus on cooling, contrary to present strategies.

Abstract This paper investigates the use of actual monitored household energy as an indicator of the thermal efficiency of a dwelling and subsequently rating of the building thermal performance. The paper reviews evaluation methods used internationally for both building thermal efficiency and building energy labelling and presents results from two discrete studies in South Australia on monitoring actual household energy consumption. In order to investigate the occupancy effect on household energy, monitored energy data collected from two different housing developments in South Australia were examined. The energy ratings for these homes are compliant with the national agreed protocols for thermal performance modelling of dwellings, where one set of homes is a group occupied by higher socio-economic groups and the other is low income public housing in a colder climate region with much poorer home energy ratings. The wide variation of actual household energy for the homes that have relatively similar thermal envelopes indicates a lack of meaningful use for actual household energy in disclosure of house energy performance. Therefore, it is argued that thermal modelling software used to rate homes appears a more useful application of a system of disclosure of energy performance than the use of energy bills.

The life cycle energy of a residential building consists of the embodied energy involved in the building materials and construction, and the operational energy of the building. Previous studies into the life cycle energy of buildings have concluded that embodied energy is a relatively small factor and can generally be ignored. A review and analysis of previous life cycle energy analysis studies was conducted re-examining this conclusion. This reevaluation has identified that this is not the case when considering climatic factors, and that in milder regions embodied energy can represent up to 25% of the total life cycle energy. The time value of carbon is generally ignored in life cycle energy analysis studies, however in a national emissions reduction regime, when the energy consumption is reduced, can become an important factor. Applying Net Present Value principles the impact of embodied and operational energy was analysed in the context of a future emissions target. It was demonstrated that embodied energy can represent 35% of the future emissions target of a building in a mild climate. The research highlights that a more wholistic approach is needed to achieve low life cycle energy buildings in the future.