• Energy Research

Based on numerical simulations, the heating load reduction effect of an attached sunspace in winter was determined, and the effective heat utilization method and sunspace design were explored. In this paper, we studied the heating load reduction effect using heat from the sunspace and temperature fluctuation of each room at the time of heat use from the sunspace (sending air from the sunspace to the heating, ventilation, and air conditioning (HVAC) machine room and taking the air to the adjacent rooms). In the case of the all-day HVAC system, it was confirmed that a larger capacity of sunspace and not sending air from the sunspace to the adjacent room demonstrated a better heating-load reduction effect. Compared with Model Iw (a house with a window on the exterior of the sunspace opened to external air), Model I (a house with an attached sunspace on the second floor) could save approximately 41% of the total energy. Model II (a house with the attached sunspace both on the first and second floors) could save approximately 84% of the total energy. Sending heat from the sunspace to the adjacent room led to temperature increases in the adjacent rooms. However, if the construction plan is to have the sunspace only on the second floor, the house should be carefully designed, for example, by placing a living room on the second floor.

Abstract This paper presents a study on a mechanically ventilated Trombe wall that adds additional windows to the storage wall. The mechanically ventilated Trombe wall is located on the south side of the house with a central air conditioning and air circulation system. To reduce the heating load, during the heating period, the heat from the Trombe wall air channel is sent to the air conditioning room, from where it is then distributed and stored throughout the house by way of air circulation. Taking a house located in Miyazaki, Japan as an example, we conducted an actual survey to understand the situation of heat utilization of the Trombe wall and used numerical simulations to examine the effective method of heat utilization of the Trombe wall. Results showed that in all-day air conditioning, even when sending the air in the Trombe wall to the air-conditioned room, the temperature of the Trombe wall remained high. The heating load was reduced by sending the air from the Trombe wall to the central air-conditioned room and installing the large heat capacity material on the floor in the Trombe wall.

In this paper, we propose a new intelligent temperature-controlled ventilated double-layer Trombe wall system for cold climate zones. This system consists of an insulation layer, an inner air chann...

This paper investigates the thermal performance and energy-saving potential of the sunspace of an old apartment building in Qingdao through experiments and software simulations. This study found that different modes of user behavior can have a substantial impact on the thermal performance of the studied sunspace in winter. The bedroom with a non-ventilated sunspace showed a higher average temperature than the bedroom without the sunspace. However, the bedroom with the sunspace had more heat loss than the bedroom without the sunspace when the sunspace was naturally ventilated, especially at night. In Delta temperature (DT)-controlled ventilation mode, the heating load of a bedroom can be reduced by 2.94 kWh/m2 compared with the non-ventilated mode. Simply optimizing the roof configuration of the sunspace can significantly improve the heat gain of the non-ventilated sunspace and reduce the energy consumption for heating by 26 kWh/m2. Compared with the unoptimized sunspace, the optimized ventilated sunspace can reduce the heating load of the bedroom by 38.82 kWh/m2. In addition, the overheating of the room in summer can be solved by opening the exterior windows of the sunspace for ventilation during the day and leaving the door of the sunspace open at night.

This study investigated the energy conservation of a non-insulated old apartment with a ventilated sunspace in Qingdao, China. The ventilation between the bedroom and sunspace of the apartment was ...

A photovoltaic shading device (PVSD) is a promising technology that can both generate electricity and provide shading to reduce indoor energy consumption. This paper aims to evaluate the performance of three PVSD design strategies in five Chinese cities by using a proposed all-in-one simulation program, according to the parametric performance design method. The program can be used to predict the energy consumption, power generation, and economic feasibility of different PVSD strategies. It was, firstly, calibrated through an actual experiment which was carried out in Qingdao and, secondly, used to simulate the energy consumption and generation of the three PVSD strategies in relation to the optimal angles and heights. Finally, the program was used to calculate the energy efficiency and economic feasibility of the three strategies. The findings indicated that the move-shade strategy of PVSD can provide the best energy-saving performance, followed by rotate-shade and fixed-shade strategies. Compared to the no-shade strategy, the reduction of the net energy use intensity by using the move-shade strategy was 31.80% in Shenzhen, 107.36% in Kunming, 48.37% in Wuhan, 61.79% in Qingdao, and 43.83% in Changchun. The payback periods of the three strategies ranged from 5 to 16 years when using the PVSD in China.