Abstract

Considering the 66% share for cooling and 3% for building heating in Saudi Arabia, the effect of PCM on reducing energy consumption by focusing on summer setpoint temperatures $({\mathrm{ST}}_{\mathrm{summer}})$ was examined. A 2 cm layer of RT-25HC (22–26$°\mathrm{C}$) was added to the wall and ceiling with thermal resistances of 0.723 and 1.057$\mathrm{ }\frac{{\mathrm{m}}^2.\mathrm{K}}{\mathrm{W}}.$ At ${\mathrm{ST}}_{\mathrm{summer}}=22°\mathrm{C},$ RT-25HC resulted in an energy saving of 8.12$\mathrm{ }\frac{\mathrm{kWh}}{{\mathrm{m}}^2}.$ As ${\mathrm{ST}}_{\mathrm{summer}}$ increases to $25°\mathrm{C},$ the energy saving reaches 55.54 $\frac{\mathrm{kWh}}{{\mathrm{m}}^2}$ (maximum value). A further increase in ${\mathrm{ST}}_{\mathrm{summer}}\mathrm{ }$ reduces energy saving to 39.69 kW (at 27$°\mathrm{C}$). In this study, the effects of RT-25HC thickness were also discussed and it was observed that thickness increasing had undesirable results. The presence of RT-25HC increases the thermal resistance, hence reduces the heat exchange, if PCM does not undergo the phase change. If RT-25HC has a phase change, increasing its thickness boots heat transfer which is not advantageous. However, at thickness 3 cm, RT-25HC is still useful, and under the best conditions, energy saving was 41.1$\mathrm{ }\frac{\mathrm{kWh}}{{\mathrm{m}}^2}.$

摘要

考虑到沙特阿拉伯 66% 的制冷和 3% 的建筑供暖份额，PCM 通过关注夏季设定温度降低能耗的效果$({\mathrm{英石}}_{\mathrm{夏天}})$被检查了。2 厘米厚的 RT-25HC 层（22–26$°\mathrm{C}$) 被添加到热阻分别为 0.723 和 1.057 的墙壁和天花板$\mathrm{ }\frac{{\mathrm{米}}^{\mathrm{2个}}.\mathrm{钾}}{\mathrm{W}}.$在${\mathrm{英石}}_{\mathrm{夏天}}=22°\mathrm{C},$RT-25HC 导致节能 8.12$\mathrm{ }\frac{\mathrm{千瓦时}}{{\mathrm{米}}^{\mathrm{2个}}}.$作为${\mathrm{英石}}_{\mathrm{夏天}}$增加到$25°\mathrm{C},$节能达到55.54$\frac{\mathrm{千瓦时}}{{\mathrm{米}}^{\mathrm{2个}}}$（最大值）。进一步增加${\mathrm{英石}}_{\mathrm{夏天}}\mathrm{ }$将节能减少到 39.69 kW（在 27$°\mathrm{C}$). 在这项研究中，还讨论了 RT-25HC 厚度的影响，并观察到厚度增加会产生不良结果。如果 PCM 不发生相变，RT-25HC 的存在会增加热阻，从而减少热交换。如果 RT-25HC 有相变，增加其厚度会促进传热，这不是有利的。不过在3cm厚的情况下，RT-25HC还是很有用的，最佳状态下节能41.1$\mathrm{ }\frac{\mathrm{千瓦时}}{{\mathrm{米}}^{\mathrm{2个}}}.$