Sustainable energy and thermal retrofit design of buildings or districts has a strong global impact in the viewpoint of economies and energy-efficiency perspectives. Several aspects such as architectonic design, building materials, construction technology, mechanical systems and outdoor climate determines the thermal behaviour of buildings and their ability to provide indoor thermal comfort to occupants. The use of geothermal energy and phase change materials (PCMs) in the construction systems are an opportunity that may attenuate indoor air temperature fluctuation as well as overheating risk. This paper presents the results of a study on indoor thermal comfort and energy efficiency regarding the PCM’s positive role when applied to new constructive solutions, inside a building with a geothermal system linked to the air conditioning system. The PCM study was based on real and simulated investigations in two rooms of a new university department at the Aveiro campus. Higrothermal monitoring (indoor air temperature) of two rooms in which one of them has PCM panels incorporated into gypsum board partition wall and into a suspended ceiling. The scope was driven to investigate the potential of these solutions for overheating mitigation. The numerical study was conducted by using an evolutionary algorithm coupled with the software EnergyPlus® used in simulations. In the scope of this optimization process, constructive solutions with the incorporation of different types of PCM with different melting temperatures and enthalpy, and different flow rates of natural ventilation were combined to investigate the potential and the payback time of these novel solutions.

The results for the room measurements show that the indoor thermal comfort of the rooms, present long periods of discomfort namely in overheating. However, it was proved that the PCM application in one of the rooms lead to an overheating reduction of 7.23% representing a PCM efficiency of 35.49%. After the optimization process an overheating reduction of about 34% was attained by the use of PCM in one of the rooms. Regarding the economic analysis of the use of the PCM for cooling demand reduction, a payback time of 18 years was attained.

从经济和能源效率的角度来看，建筑物或区域的可持续能源和热力翻新设计对全球具有重大影响。建筑设计，建筑材料，建筑技术，机械系统和室外气候等几个方面决定了建筑物的热性能及其为居住者提供室内热舒适的能力。在建筑系统中使用地热能和相变材料（PCM）是减少室内空气温度波动以及过热风险的机会。本文介绍了在将地热系统与空调系统相连的建筑物内部，将PCM在应用于新的建筑解决方案中时所发挥的积极作用的室内热舒适性和能源效率的研究结果。PCM研究是基于对阿威罗校区新大学系的两个房间进行的真实和模拟调查得出的。对两个房间进行高温热监测（室内空气温度），其中一个房间的PCM面板集成在石膏板隔墙和吊顶中。驱动范围来研究这些解决方案对缓解过热的潜力。数值研究是通过使用进化算法以及模拟中使用的软件EnergyPlus®进行的。在此优化过程的范围内，结合了具有不同熔化温度和焓以及不同自然通风流量的不同类型PCM的建设性解决方案，以研究这些新颖解决方案的潜力和投资回收期。

房间测量的结果表明，房间的室内热舒适性长期存在不适感，即过热。然而，事实证明，在其中一个房间中使用PCM可使过热减少7.23％，表示PCM效率为35.49％。在优化过程之后，通过在其中一个房间中使用PCM达到了约34％的过热减少。关于使用PCM降低制冷需求的经济分析，回收期为18年。