Simulation study on suppressing temperature fluctuation based on PCM for radiant supply cooling systems in thermodynamic measurement laboratory

Temperature precision control is one of the most critical issues in metrology laboratories, and this issue has become increasingly stringent in modern society. Radiant air conditioning system, which minimizes vibration through radiant heat transfer instead of conventional convection, has gained attention but is more sensitive to temperature fluctuations from the cooling source. Considering that phase change materials (PCMs) have the advantage of suppressing water temperature fluctuations, comparative simulations are carried out to analyze the suppressing effectiveness by adding two typical PCMs (paraffin and dimethyl sulfoxide) in water tanks and radiant panels separately. Results indicate that adding paraffin to water tanks has a better effect than dimethyl sulfoxide while it is inverse for radiant panels. Then, the adding volume ratios (paraffin for the water tank is 0.2; dimethyl sulfoxide for radiant panels is 0.1) are provided, when surface temperature fluctuations of radiant panels are suppressed within ±0.1 K. Finally, the relationship between the latent heat/thermal conductivity of PCM versus suppressing effect is investigated to provide a reference for the design of radiant air conditioning systems in metrology laboratories.