جستجوی مقالات مرتبط با کلیدواژه « humid climate » در نشریات گروه « مکانیک »

In this research, with the help of thermodynamic modeling of an XU7 engine (manufactured by Irankhodro Co.), the effect of insulation and modification of the intake air route (IAR), in a real hot and humid weather case study(49 ° C and 20.2% relative humidity similar to a normal summer day of Khuzestan state climate) is investigated. In this regard, assuming hot engine run-up and naturally aspiration condition, the thermodynamic model of the processes of a spark ignition engine, based on the Anand combustion model, was developed. In the process of modeling the irreversible work of viscous friction caused by lubrication of pistons and rings, assuming the constant viscosity of the lubricant as well as two compression rings for each piston, was considered. The physical effects of the presence of moisture in the engine intake air(EIA) were taken into account. Considering two different cases, the effect of heat transfer to EIA was applied. Case 1: gradual heat transfer approach along IAR and case 2: heated air suction approach before entering IAR (This approach is closer to reality). The cylinder body temperature as well as the equivalence ratio in the combustion process are considered constant at all crank angular velocities. The results were verified by reputable authorities. The results showed that reducing the EIA temperature due to the insulating IAR is effective for each of the above two cases. But in the second case, this action has a greater impact. Based on the results, the effect of insulating IAR of the XU7 engine in the mentioned weather conditions can be simultaneously, Leads to a 12% increase in engine output power (at 6000 rpm) and also a 10.3% increase in engine output torque (at 1000 rpm).

This study focuses mainly on employing trombe wall systems to provide the heat required for restoring the desiccant wheel and investigating the optimal surface area of the wall for attaining air conditioning comfort. In this study, a solar desiccant wheel was modeled that receives the thermal energy required for regeneration from a trombe wall. In this system, first, the components of the desiccant wheel, the trombe wall, and the insolation were separately modeled in MATLAB and then assembled. The integrated system may be examined in all humid weather conditions around the globe. The results of the model are compared with the experimental results and have acceptable agreement with each other. The model had been developed for cooling the building in July in Rasht city by using the ground heat exchanger. A ground coil was incorporated in this system to pre-cool the process air. The optimal surface area of the trombe wall was extracted as a function of the parameters of the desiccant wheel. For a wall output temperature of 66 °C, the comfort temperature was found to be 24 °C, the humidity ratio to be 12 gw/kgra, and the optimal wall surface area to be around 52 m2.

This study focuses mainly on employing trombe wall systems to provide the heat required for restoring the desiccant wheel and investigating the optimal surface area of the wall for attaining air conditioning comfort. In this study, a solar desiccant wheel was modeled that receives the thermal energy required for regeneration from a trombe wall. In this system, first, the components of the desiccant wheel, the trombe wall, and the insolation were separately modeled in MATLAB and then assembled. The integrated system may be examined in all humid weather conditions around the globe. The results of the model are compared with the experimental results and have acceptable agreement with each other. The model had been developed for cooling the building in July in Rasht city by using the ground heat exchanger. A ground coil was incorporated in this system to pre-cool the process air. The optimal surface area of the trombe wall was extracted as a function of the parameters of the desiccant wheel. For a wall output temperature of 66 °C, the comfort temperature was found to be 24 °C, the humidity ratio to be 12 gw/kgra, and the optimal wall surface area to be around 52 m2.

Today, application of advanced materials has made opportunities to reduce energy consumption of buildings and improve life’s quality. Smart glasses are among new materials designed to prevent energy loss through windows. Smart glasses could be categorized as Electrochromic glasses, liquid crystals, Gasochromics, Thermochromics and SPDs. In this article introducing various types of smart glasses, their characteristics and thermal performance had been compared. In order to evaluate the impact of smart glasses on energy consumption of building, a small office in Bushehr, Iran has been studied using Designbuilder simulation software. The results show advantages of using smart glass in reducing solar heat gain and cooling load of building. According to the results, SPD glass has the best performance reducing cooling load of building. Gasochromic, Electrochromic and Thermochromics glasses would also reduce the cooling load respectively. While the amount of solar heat gain varies in different months of the year, the average annual solar heat gain is the lowest using SPD glasses and Gasochromic, Thermochroic and Electrochromic glasses are in the next step. Application of SPD glass would result in 48.3% reduction in buildings cooling load compare to ordinary glass. The amount of reduction for Gasochromic, Electrochromic and Thermochromics glasses would be 45.8%, 34.1% and 17.23% respectively. So application of smart glasses in hot and humid climate of Bushehr can reduce solar heat gain and thus cooling load of buildings

In this paper, phase change material (PCM) was utilized in the hydronic floor heating system for house heating in the winter. The outdoor temperature was considered moderate and humid, as the climate in North of Iran. The effect of hot water temperature in tubes, transition temperature, latent heat and finally thermal conductivity of PCMs are investigated and the operating characteristics of the system were compared with that of the non- phase change energy storage system. The results showed that the PCM stabilized temperature within the room and decreased energy consumption. Latent heat of PCM found to have a minor effect on room temperature, whereas increase in the transition temperature of PCM caused increase of the lagging time between outside and inside room temperatures. Increasing the thermal conductivity of the PCM, the rise of room temperature per unit time was accelerated, in addition, increasing the weight fraction of Nano particles in PCM was dampened the amplitude of room temperature variation during the day. Therefore, using Nano-PCM was found to be of great significance for house heating and comfort condition of occupants.