Development of novel experimental infrastructure for collection of high-fidelity experimental data for refrigerant to air heat exchangers

• Published in: International journal of refrigeration 2020-06, Vol.114, p.189-200
• Main Authors: Saleem, Saad, Sarfraz, Omer, Bradshaw, Craig R., Bach, Christian K.
• Format: Article
• Language: English
• Subjects: Accuracy; Boucle de frigorigène pompé; Circuits; Coils; Essais préliminaires; Evaporation; Evaporators; Experimental; Expérimental; Fin-and-tube heat exchangers; Heat exchangers; HVAC; Numerical models; Prediction models; Predictions; Preliminary testing; Production costs; Pumped refrigerant loop; Refrigerants; Refrigeration; Tube heat exchangers; Uncertainty analysis; Wind tunnels; Échangeurs de chaleur; Échangeurs de chaleur à tubes ailetés
• ISSN: 0140-7007; 1879-2081
• DOI: 10.1016/j.ijrefrig.2020.02.024

•Development of pumped refrigerant loop to test fin-and-tube heat exchanger coils.•It can test coils in 3 modes: single-phase refrigerant, evaporator and condenser.•Refrigerant loop combined with a wind tunnel installed in a psychrometric chamber.•Test plan and uncertainty analysis presented for first coil to be tested in the setup.•Uncertainty analysis shows that experiment can predict coil capacity within ±2%. Fin-and-tube refrigerant-to-air heat exchangers are one of the most common styles of heat exchangers in residential and light-commercial HVAC&R applications. To optimize trade-off between unit efficiency and production costs for units that use them most manufacturers rely on predictive modeling tools. High-fidelity predictive modeling tools require equally high-fidelity experimental data to validate model predictions. This paper presents the design and development of a custom-designed pumped refrigerant loop that can test fin-and-tube heat exchangers in three modes: (1) single-phase refrigerant, (2) evaporator, and (3) condenser mode. This pumped refrigerant loop will be combined with a small-scale wind tunnel installed in a psychrometric chamber facility to enable acquisition of high-fidelity data to validate recently developed segment-by-segment fin-and-tube heat exchanger numerical models (Sarfraz et al., 2019, 2020). The pumped refrigerant loop allows precise control of desired test conditions, flowrate to each heat exchanger circuit, and is sized to test heat exchangers up to a capacity of five tons. A preliminary test plan and detailed uncertainty analysis is developed for the first heat exchanger coil to be tested in the setup. The uncertainty analysis suggests that the experiment will be capable of measuring overall coil capacity within ±2%. A formalized design of experiments is also presented which suggests 9 tests per coil is a sufficient number to minimize experimental effort. A preliminary experiment was performed in evaporator mode that shows that air and refrigerant side capacities agree within 5%, which is in accordance with the energy balance limit set by ASHRAE Standard 33.