Design requirements for condensation-free operation of high-temperature cooling systems in mediterranean climate

• Published in: Building and environment Vol. 185; p. 107273
• Main Authors: Pieskä, Henrikki, Ploskić, Adnan, Wang, Qian
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.11.2020; Elsevier BV
• Subjects: Air cooling; Building retrofit; Condensation; Condensation control; Control systems; Cooling; Cooling systems; Dehumidification; Dew point; Energy consumption; Energy efficiency; Exergy; Fluid and Climate Theory; High temperature; High-temperature cooling; Radiant cooling; Retrofitting; Strömnings- och klimatteori; Systems analysis; Temperature control; Temperature requirements; Thermal comfort; Water temperature; Radiant cooling; Building retrofit; Thermal comfort; Energy efficiency; Condensation control; High-temperature cooling
• ISSN: 0360-1323; 1873-684X; 1873-684X
• DOI: 10.1016/j.buildenv.2020.107273

Radiant cooling systems are a subject of increasing scientific interest due to their efficiency and ability to use high-temperature cooling sources. In hot and humid conditions, they have generally been studied in combination with dehumidification systems. For retrofit projects, a control system that would eliminate the need for dehumidification would be beneficial. In the present study, a passive geothermal-based radiant high-temperature cooling system is studied in a Mediterranean climate. The system is operated with supply water temperature control using dew point temperature as a controlling variable. The system's performance is compared with that of an all-air cooling system. The systems are evaluated using IDA-ICE building energy simulations, validated with on-site measurement data. The results show that the radiant cooling system produces the same level of thermal comfort with 40% lower energy use and 85% lower exergy consumption than the all-air system. The risk of condensation limits the cooling capacity of the radiant cooling system. Consequently, insufficient cooling capacity causes thermal discomfort for the occupants due to the operative temperature exceeding 26 °C. •High-temperature cooling (HTC) is an energy efficient alternative to all-air systems.•Thermal comfort performance of the HTC system is as good as the all-air system's.•Comfortable operative temperature was achieved for 77% of the cooling season.•HTC system's cooling capacity is limited by risk of condensation in humid climates.•Low temperature lift required by the HTC system permits the use of geothermal heat.