The performance of box-type solar cooker very often deteriorates in winter due to less solar radiation available on the cooker surface as well as low surrounding temperature. The top heat losses that constitute the major losses from the box type solar cooker have strong influence on the thermal performance. Indoor experiments on unloaded (empty) box-type solar cooker were conducted to estimate top heat loss coefficient U{sub}t as a function of plate temperature and wind speed. A simple correlation for U{sub}t has been developed to represent the experimental results. Using the proposed correlation, heating characteristic curves for the solar cooker are obtained. It has been observed that the plate temperature in a box-type solar cooker at an ambient air temperature of 17°C and wind speed of 1.1 m/s does not reach 60°C and 90°C for solar radiation intensities of 300W/m{sup}2 and 600W/m{sup}2 respectively. Very little effect of wind speed is observed for lower values of plate temperature. The effect of lower values of ambient air temperature on the heating characteristics of cooker has also been investigated.
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机译：由于在炊具表面上可用的太阳辐射较少以及围绕围绕温度，因此盒式太阳锅式烹饪器的性能通常在冬季劣化。构成箱式太阳能炊具的主要损失的顶部热量损失对热性能产生了很强的影响。在卸载（空）箱式太阳炊具上的室内实验被进行以估计顶部的热损耗系数U {Sub} T作为板温度和风速的函数。已经开发了对U {Sub} T的简单相关性以表示实验结果。使用所提出的相关性，获得太阳炊具的加热特性曲线。已经观察到，箱式太阳能炊具的板温度在17°C的环境空气温度下，风速为1.1 m / s，对于300W / m的太阳辐射强度而不达到60°C和90°C分别为{sup} 2和600w / m {sup} 2。对于较低的板温值，观察到风速的影响很小。还研究了较低的环境空气温度值对电磁炉加热特性的影响。
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