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    Cooling demand reduction with nighttime natural ventilation to cool internal thermal mass under harmonic design-day weather conditions
    (Elsevier Ltd, 2025-02-01) Li M; Shen X; Wu W; Cetin K; Mcintyre F; Wang L; Ding L; Bishop D; Bellamy L; Liu M
    Cooling demand is steadily increasing across different climate zones due to global warming. A potential solution for cooling demand reduction is applying nighttime natural ventilation to cool internal thermal mass. However, a simplified and accurate modelling framework to assess the technique is still missing. The goal of the study is to build that framework integrated with a validated internal thermal mass model and apply the framework to quantify the cooling demand reduction potential in a space with different thermal mass and envelope configurations and in different climate zones. Results show that using Granite as internal thermal mass is three times more effective than concrete to reduce peak cooling load. Adding too much internal thermal mass can create adverse effects on cooling load reduction. The optimum thickness of internal thermal mass is between 28 and 45 mm. Envelope construction also has an influence on the performance of nighttime cooling. Applying the technique in buildings with lightweight structures reduces peak cooling load by 35.9% more than heavyweight structures. As heavyweight structures delay the release of the daily absorbed heat and cause higher indoor air temperatures at night. The two belts between the Tropic of Cancer and 60 degrees north latitude, and between the Tropic of Capricorn and 45 degrees south latitude are suitable for nighttime natural ventilation of internal thermal mass, achieving the annual cooling demand reduction above 1.25 kWh m−2. In Dessert climate zones, the technique exhibits an extraordinary potential to reduce cooling demand, up to 6.67 kWh m−2 per year.
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    Selected solar design tools for sustainable residential land development : a thesis presented in fulfilment of the requirements for the degree of Master of Engineering at Massey University
    (Massey University, 2005) Duncan, Andrew
    As New Zealand's natural gas reserves decline and electricity demand growth exceeds the building of new generation plants, greater focus needs to be applied to energy efficient design in domestic buildings and land developments. A case study of residential land development was analysed in terms of its potential for energy efficiency gains and optimisation of solar resources. A design tool was developed to rapidly assess the solar energy loss of a specific building site due to existing land features. 'Solar obstruction contours' were produced that define the maximum permissible height of obstructions before solar shading occurs. These contours were produced based on a minimum percentage solar energy capture. Thermal energy demand for the development case study was calculated by specification of a Building Performance Index relative to floor area. The demand was then balanced against on-site thermal energy production from biomass to give a percentage thermal energy self sufficiency. The tools developed can be used to optimise the design of a residential land development resulting in an increase in renewable energy use above that of standard residential developments. The study concluded that incorporation of the tools as standard practice by municipalities is viable, and if implemented would increase the energy efficiency and renewable energy use of the New Zealand housing stock.