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The purpose of the research was to examine the savings potential and verify how to reduce the energy consumption in new hospitals by about 50%. Our results are also very relevant in other buildings complex with surplus heating, cooling and thermal storage. Conversion and utilization of surplus heat sources represent well known technologies and are under constant development. In large building complexes there is a potential for coordinated production, storage, and distribution of energy. Heat pump, chiller and thermal storage technologies enable re-use of surplus heat/cool energy throughout the year. Energy supply and demand are typically modelled with separate tools and timescales. Through our study new methods are developed for operation of interacting simulating models. These methods provide tools to step into optimization of combinations of integrated energy systems. The main issues focus on hydraulic water flow and storage systems as a basis. The layout is important not only with regards to utilize the energy quality, i.e. the temperature. In addition, control strategies are shown to have a highly relevant impact on the possible savings. Some details of new hydraulic layout and control design will be described and discussed in the paper. Both in combination with heating, cooling and storage system. Our research indicates that it is possible to save between 20-50% of the energy consumption with optimizing the technical installations in Oslo area. Another benefit of integrated thermal modelling is to reduce the risk of permafrost in ground source heat pump installations. This risk is relevant for large buildings in northern Norway, at annual mean temperatures are below 0̊C. This paper shows how integrated simulation and design can be used to avoid permafrost. [ABSTRACT FROM AUTHOR]

Abstract: The article described the dilatancy technology of district heating system with high-temperature heat pump (HTHP). For the exploitation of low-temperature return network sources, a high-temperature heat pump with a heat exchanger was planned. As the core technology of the dilatancy district heating system, HTHP units and heat exchanging systems had been described detailedly through theoretical and experimental analysis. The model was proved to be in good agreement with the experiment data. It could be used for engineering design. In this paper the district heating system in Datong was taken as a case study. The main characteristics of the dilatancy district heating system had been presented in the form of diagrams. The principal advantage of dilatancy technology in the district heating system lies in increasing the temperature difference, reducing the diameters and the initial investment of primary side network. This paper shows clearly the analysis of the dilatancy technology for characterising and improving the performance of district heating systems. [Copyright &y& Elsevier]

As one of the energy-efficient heating technologies, earth air heat exchangers (EAHE) use renewable energy (i.e. geo-thermal energy) to first heat outdoor air, and then supply it to indoors for space heating in winter. The aim of this paper is to study the thermal performance of EAHE in winter in hot summer and cold winter areas. An experimental setup of EAHE was established in Changsha, China. Different variables, including soil temperature, supply air temperature and outdoor air temperature were measured for one week. The thermal performance was evaluated based on the data analysis. Results show that the supply air temperature reached the soil temperature around the pipe at the same length of 20m for different inlet air temperature. The COP and Q decreased along with the increase of inlet air temperature but increased along with the pipe length. Moreover, the thermal saturation of soil occurred in the fifth day of the week, and thermal interference between pipes can be ignored under the 1m distance between pipes. Our future work includes developing a numerical model to analyze and optimize the thermal performance of EAHE, thereby providing a reference for its design and application in hot summer and cold winter areas in China. [ABSTRACT FROM AUTHOR]

• A new enclosed melting system was built for deicing the bottom of a train. • A new method was used for simulating gravity shedding melting in complex models. • The effect of supply air properties on system performance was studied. In winter, a large amount of icing and snowing occurs in outdoor equipment and systems, which adversely affects their lifespan. The melting process is divided into two parts: convection melting and gravity shedding melting. This paper is based on an experiment with a real high-speed train unit, and it establishes a three-dimensional computational fluid dynamics model of the bogie area to validate the mathematical model of the winter ice melting experiment. A numerical simulation was used to calculate the airflow in the baffle-enclosed space and to predict the effects of interactions between air and the ice body on heat transfer and phase change. The influence of air velocity and temperature on the heat transfer was analyzed. The computational simulation effectively quantifies the amount of heat transfer and energy consumption under different conditions. This paper also presents a research method for the simulation of gravity shedding in complex models. These models provide information for the construction of similar ice melting models. This paper has suggested that for thin ice bodies, convection melting was the dominant strategy. For thick ice bodies, however, gravity shedding melting became dominant. The study also confirmed that enclosed hot-air ice-melting systems gave a better energy performance than unenclosed systems. [ABSTRACT FROM AUTHOR]

• A new methodology to investigate the impact of thermal mass is defined. • The use of unrepresentative boundary conditions could lead to inaccurate conclusions. • High thermal mass helps to decrease and regulate the internal temperature. • High thermal mass could increase energy use in the summer and winter seasons. • Isolating thermal mass through internal insulation results in better energy performance than external insulation. Contradictory conclusions have been reported on whether thermal mass reduces or increases energy demand in hot and cold climates. A novel approach to measuring the impact of thermal mass on the building's energy consumption is presented. The method aims to better represent reality and applies two different control conditions simultaneously in a numerical model: the first condition, which has been used in past studies, adjusts the internal boundary condition based on the time duration of heating/cooling activation (simulating an occupancy pattern) and the second, which has not been used in past studies, adjusts the internal boundary condition based on both the time duration and the internal temperature (simulating an occupancy pattern and the thermostatic control system). When investigating the impact of thermal mass on the internal temperature in a scenario where no heat is transferred into the building, the high thermal mass outperforms the low thermal mass, showing a time-shifting effect, long time lag, and small decrement factor. However, when modelled using the method presented in this paper, high thermal mass results in greater energy consumption during summer and winter periods in Saudi Arabia. During transition seasons where temperature swings occur on either side of the indoor set-point temperatures, thermal mass reduces thermal transmission. The impact of thermal mass is also investigated for several climatic conditions in Saudi Arabia. Simulation results show that an internally exposed thermal massive wall section results in greater energy consumption when compared to a similar building with isolated thermal mass (i.e. insulated internally). This is due to the fact that even though the internal temperature inside the building is being cooled/warmed up to the set-point, the thermal mass continues to transfer heat that is absorbed by the building's fabric from/to the interior, placing a greater demand on the cooling/heating system. Over the course of a year, however, the impact of thermal mass is negligible when compared to other factors, such as the insulative properties of the building's fabric. [ABSTRACT FROM AUTHOR]

Abstract: This paper studied the annual thermal performance of a photovoltaic wall (PV wall) mounted on a multi-layer façade. Based on some developed unsteady-state heat transfer models for a PV wall and a normal wall, the annual thermal performance of two types of walls was simulated. Compared with a normal wall, the south-facing PV wall could reduce heat gain through the envelope by 51% in summer under Hong Kong weather conditions. The impact of the PV wall on the envelope’s heat gain and heat loss in winter was investigated for the first time, and the results indicated that the PV wall could not only significantly reduce the heat gain through the envelope in daytime, but also reduce the heat loss at nighttime. The heat gain and heat loss through the PV wall in winter were reduced by 69% and 32% respectively compared with a normal wall. Totally, an annual thermal energy consumption reduction of 52.1kWh was achieved by replacing each square meter of a south-facing normal wall by a PV wall, which is equivalent to a saving of 18.6kWh of electric energy for the air conditioning system in a building. The impact of the thickness of an air duct on the thermal performance of the PV wall was also discussed. [Copyright &y& Elsevier]

Abstract: When an air source heat pump (ASHP) unit operates in heating mode, frost can be accumulated on the surface of its finned outdoor coil which normally has multiple parallel circuits on its refrigerant side for minimized refrigerant pressure loss and enhanced heat transfer efficiency. On its airside, however, there is usually no segmentation corresponding to the number of refrigerant circuit. Frosting deteriorates the operation and energy efficiency of the ASHP unit and periodic defrosting becomes necessary. Currently the most widely used standard defrosting method for ASHPs is reverse cycle defrost. This paper, the first part of a two-part series, reports on the experimental part of a study of the reverse cycle defrosting performance on a multi-circuit outdoor coil unit in an experimental 6.5kW heating capacity residential ASHP unit. Firstly the experimental ASHP unit is described and experimental procedures detailed. Secondly, the experimental results are reported. This is followed by the discussion on the effects of downwards flowing of the melted frost along a multi-circuit outdoor coil surface on defrosting performance. Finally, the evaluation of the defrosting efficiency for the experimental ASHP unit is provided. In the second part of the series, a modeling analysis on the effects of downwards flowing of the melted frost along the multi-circuit outdoor coil surface on defrosting performance of the experimental ASHP unit will be presented. [Copyright &y& Elsevier]

Abstract: An energy cost allocation system records the energy consumption of a building and divides the overall energy costs between the flats. Because the indoor temperatures of rooms are usually not equal, static heat flows between flats cannot be avoided. Hence, in order to ensure fair energy costs per flat the system should be able to determine the static heat flows, preferably without utilising in situ measurements. This paper presents a new method for estimating static heat flows between neighbouring rooms. The approach is theoretical, focusing only on heat transfer issues. Energy cost allocation is not considered. The approach is based on the parametric model describing thermal behaviour of an occupied space. The model is created for each room of a building. Parameter values are identified using real-time measurements collected by a building automation system from each room and its environment. The tuning of parameters takes a few days using a 15-min sampling time. A prerequisite for successful system identification is the overall control of the room temperatures. All test runs are performed in a simulated office hotel using the TRNSYS simulation program. The results are encouraging, but further research is needed, especially in a real building environment. [Copyright &y& Elsevier]