Infrastructure Engineering - Research Publications

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    Undisturbed ground temperature in Melbourne
    Shah, SK ; Aye, L ; Rismanchi, B ; Sadrul Islam, AKM ; Ruhul Amin, M ; Ali, M (AIP Publishing, 2019-07-18)
    The ground surface temperature changes with the diurnal cycle of solar radiation and ambient air temperature. However, the amplitude of the ground temperature variation diminishes with the increase of the depth of the ground and after a certain depth of the ground, it becomes almost constant, where is termed "undisturbed ground temperature (UGT)". At this depth, the seasonal changes of solar radiation and ambient air temperature changes will no longer affect onground temperature. It is one of the important parameters for designing of the ground heat exchangers and building energy analyses. In this study ground temperatures at various depths in Melbourne were investigated using a 40 m deep borehole instrumented with thermistors. The ground temperatures at various depths (0 m to 40 m) in Melbourne were also simulated by using three methods: Kasuda formula method, simulation (TRNSYS, Type 77), and simplified correlation (developed by Ouzzane et al. in 2015) and the results were compared with the measured data. Root mean square error (RMSE) and mean bias error (MBE)were used to validate and verify the methods. It was found that the estimated ground temperatures at 2, 21, and 40 m depths by Kasuda formula method and simulation (TRNSYS)have the same trends as that of the measured data. The measured annual temperatures of ground at 2 m depth were between 14.7°C and 19.8°C, while the temperature at 21 m and 40 m depths remained almost constant. RMSE and MBE of the simulation (TRNSYS, Type 77) were found to be 1.39°C, and -1.39°C respectively compared to measured data at 21 m depth. Based on these values, we conclude that simulation (TRNSYS, Type 77) can reliably predict the ground temperature for the selected site in Melbourne.
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    Seasonal solar energy storage system for space heating in cold climate
    Shah, SK ; Aye, L ; Rismanchi, B (Australian PV institute, 2017-12-05)
    A seasonal solar energy storage system for space heating in cold climates is proposed. The system includes evacuated tube solar collectors integrated with double U-tube vertical borehole thermal storage coupled with a heat pump. The performance of the system is evaluated by computer simulations for a cluster of typical houses in four Asia-pacific cities: Ulaanbaatar (Mongolia), Harbin (China), Dras (India) and Lukla (Nepal). TRNSYS, a transient systems simulation program, was used to simulate the system. The typical detached house model for each city was developed based on the type of dwelling. The initial sizes of the system components were determined for the four cities. The average ground temperatures and energy balance of the system during charging and discharging modes were investigated. The seasonal heating coefficient of performance of the system in each city has been presented. The simple payback period (SPBP) of the proposed system was investigated by comparing convention system. It was found that the proposed system has the potential for fulfilling the space heating demand in cold climate cities of Asia-Pacific region.
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    Net zero fossil energy for heating detached houses in Harbin
    Shah, SK ; Rismanchi, B ; Aye, L (ZEMCH Network, 2018-01-29)
    Following the recognition of the zero energy building concept, the zero energy mass customised houses have received more attention recently. This paper investigates the application of solar energy to achieve net zero on-site energy for space heating in a cold climate. As a case study, a cluster of 30 typical houses in Harbin, China was considered. Harbin is known for its coldest weather and longest winter among major Chinese cities. This study used TRNbuild software to model the house and consequently TRNSYS to determine the total heating load of the cluster of houses. The study focused on fulfilling the heating demand by using a ground source heat pump (GSHP) system. The total electricity consumed by the GSHP is covered by a grid-connected solar photovoltaic (PV) array. The required area of PV array to meet 100% of the annual electricity consumed by the GSHP was calculated. The results show the peak GSHP electric load required for the cluster of houses to be 99 kWhe with the total PV array area of 1961 m2. The levelised cost of electricity (LCoE) generated by the PV array was found to be US$ 0.067 (RMB 0.44) per kWhe for 30-year project life. The cost of heat distribution network, the annualised life cycle cost (ALCC), and the unit heating cost (UHC) were also estimated for the system investigated.