Search

Airflow windows (AFWs) help to stabilize the thermal environment in the perimeter zone and also allows for switching between solar‐shielding and solar heat acquisition operations. This is based on the method of channelizing the air discharged from its cavity layer, either by using a total heat enthalpy exchanger and choosing to exchange heat or otherwise. It has a certain thickness owing to the blinds that are installed in its cavity layer. The purpose of this research is to develop a window system that uses electrochromic (EC) glass, instead of blinds, as a solar‐shielding device. This study also provides the specifications of the window system of reduced thickness. The performance of the window system is assessed by CFD analysis. The solar heat gain coefficient (SHGC) of the proposed window system is found to range from 0.083 to 0.268 and its solar radiation properties can be controlled in a flexible manner. These characteristics contribute to an improvement in the building environmental performance in the form of climate‐adaptive building shells (CABS) in places with four distinct seasons such as Japan that require solar‐shielding to reduce the cooling load in summer and solar heat gain to reduce the heating load in winter. [ABSTRACT FROM AUTHOR]

Here, a new energy‐saving optimization method, known as the Improved Particle Swarm Optimization (IPSO) algorithm, is proposed to solve the practical engineering problem of high energy consumption during the operation of central air‐conditioning water systems. The mathematical model of total energy consumption optimization and the calculation principle of the IPSO are established. It is shown via experiments that the proposed algorithm requires a short optimization time and can achieve the optimal operation conditions of water systems under various cooling loads, where these conditions include the optimal control strategy of equipment, and water temperature at the inlet and outlet of chillers. Furthermore, it ensures the lowest energy consumption of water system operation. The measured results show that the comprehensive energy saving rate of water system operation can reach more than 18% compared with that before the system transformation. [ABSTRACT FROM AUTHOR]

In hot‐arid climatic regions like Qatar, it is important to facilitate pedestrians' journeys. One way to do so is by providing them with shelters, that is, from a station to their destination building. It is necessary for such shelters to provide on‐site space cooling and freshwater in an off‐grid condition. In this respect, the proposed off‐grid system in this study includes bifacial photovoltaic (BPV) and a solar thermal collector for energy generation with battery and thermal storage units. BPV with an efficiency of 16% can produce power up to about 6.1 kW on the rooftop, which also reduces the cooling load via effective shading. The ejector‐based cooling system is deployed for efficient space cooling in high ambient temperatures (more than 28°C), while for less than 28°C, both fan and water misting systems are operated for the comfort of pedestrians. Finally, an electrodialysis system is integrated to generate freshwater from seawater to be used for drinking and water misting purposes in the off‐grid sustainable shelter. The overall energy and exergy efficiencies of the system are calculated to be 13.2% and 5.29%, respectively. The effects of several parameters are also studied to observe the overall system efficiency and the energy generated and consumed by the system. [ABSTRACT FROM AUTHOR]

To overcome the problem of walking in the scorching heat and to encourage people to use more public transport (ie, trams and metros), the idea of sustainable climate refuge shelter is highly needed. In this study, the proposed shelter includes semi‐transparent photovoltaic cells located on the roof integrated with batteries to keep the system running at nighttime and in unfavorable irradiation conditions. An atmospheric water generator for freshwater production is employed for drinking and water misting in addition to a vapor compression cooling system with a fan. Freshwater is collected by extracting water from humid air through cooling with dehumidification. The system is analyzed thermodynamically through energy and exergy efficiencies. The overall energy and exergy efficiencies of the system are 19.45% and 9.58%, respectively. The electrical efficiency of the photovoltaic cells decreases from 16.87% to 15.24% with an increase in cell temperature from 309 K to 315 K. Hourly analysis of the proposed system for the whole year is performed to evaluate the energy profile. The proposed system generates electricity in winters that is sufficient to keep the system operational for 2 days (only for drinking water requirement), but in the summers, only 24 h due to extensive cooling load. The effects of several parameters such as irradiance, ambient temperature, relative humidity, transmittance, and occupancy rate are studied. [ABSTRACT FROM AUTHOR]

This research is proposed to fully investigate the performance of a single‐effect water/lithium bromide absorption chiller driven by geothermal energy. Since absorption cycles are considered as low‐grade energy cycles, this innovative idea of rejecting fluid from a single‐flash geothermal power plant with low‐grade energy would serve as efficient, economical, and promising technology. In order to examine the feasibility of this approach, a residential building which is located in Sharjah, UAE, considered to evaluate its cooling capacity of 39 kW which is calculated using MATLAB software. Based on the obtained cooling load, modeling of the required water/lithium bromide single‐effect absorption chiller machine is implemented and discussed. A detailed performance analysis of the proposed model under different conditions is performed using Engineering Equation Solver software (EES). Based on the obtained results, the major factors in the design of the proposed system are the size of the heat exchangers and the input heat source temperature. The results are presented graphically to find out the geofluid temperature and mass flow and solution heat exchanger effectiveness effects on the chiller thermal performance. Moreover, the effects of the size of all components of the absorption chiller on the cooling load to meet the space heating are presented. The thermal efficiency of the single‐flash geothermal power plant is about 13% when the power plant is at production well temperature 250℃, separator pressure 0.24 MPa, and condenser pressure 7.5 kPa. The results show that the coefficient of performance (COP) reaches about 0.87 at solution heat exchanger effectiveness of 0.9, when the geofluid temperature is 120℃. [ABSTRACT FROM AUTHOR]

A rate‐based model of an absorption column was developed and used to analyze several intercooling strategies utilizing "heat exchange packings." These packings are capable of removing heat from the column and transferring it to a cooling fluid within the packing. For absorption of CO2 into aqueous monoethanolamine under industrial conditions, intercooling via heat exchange packings placed along 10–20% of the column could reduce the column height by ∼15%. The height of these columns was close to the minimum theoretical value, calculated by numerically optimizing the temperature profile. Effective intercooling could also be achieved by using the cool, rich solvent as the cooling fluid. This reduces the cooling load and facilitates recovery of waste heat. Heat exchange packings could also be used to redistribute heat within the column, reducing the column height with no net cooling load. However, this approach requires larger heat transfer coefficients than have been experimentally observed. [ABSTRACT FROM AUTHOR]

The building energy consumption and energy saving rate in office buildings with Dye‐doped liquid crystal (DLC) smart window under the change of region, window‐wall ratio and orientation were simulated by DeST‐C. The results indicated that the energy saving rate of DLC smart window increased with the rising proportion of cooling load in different regions: Harbin < Beijing < Shanghai < Guangzhou. When DLC smart window was used in Shanghai, the energy saving rate increased with the increase of window‐wall ratio. Moreover, DLC smart window in different orientations generally resulted in different energy saving rate: North < South< East