Open Daily: 10am - 10pm | Alley door pickup 10am - 7pm 3038 Hennepin Ave Minneapolis, MN
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  • Open Daily: 10am - 10pm
    Alley-side Pickup: 10am - 7pm

    3038 Hennepin Ave Minneapolis, MN
    612-822-4611

Open Daily: 10am - 10pm | Alley-side Pickup: 10am - 7pm
3038 Hennepin Ave Minneapolis, MN
612-822-4611
Improving the Performance of a Roof Top Air-Conditioning Unit by Refrigerant Circuitry Optimization

Improving the Performance of a Roof Top Air-Conditioning Unit by Refrigerant Circuitry Optimization

Nist

Paperback

General Science

ISBN10: 1496033191
ISBN13: 9781496033192
Publisher: Createspace
Published: Feb 24 2014
Pages: 74
Weight: 0.43
Height: 0.15 Width: 8.50 Depth: 11.00
Language: English
This study demonstrates the performance improvement of an air-to-air roof top unit (RTU) achieved by optimizing an evaporator0/00s refrigerant circuitry using evolutionary algorithms. The subject of this study is a unit with a cooling capacity of 7.5 Tons (26.4 kW). The RTU employs two separate refrigerant cycles having separate compressors, condensers, and thermostatic expansion valves (TXV) but using a single evaporator slab in which two separate refrigerant circuits are implemented. We modified the RTU by replacing the refrigerant-to-air condensers with water cooled brazed plate heat exchangers in order to facilitate testing. Performance tests were conducted in a conditioned environmental chamber in line with AHRI standard 340/360; in order to accomplish this, we maintained the liquid line saturation pressure and subcooling from the manufacturer0/00s test data by adjusting the condenser water flow rate and temperature. We also measured the in-situ air velocity profile using Particle Image Velocimetry (PIV), a non-intrusive, laser-based technique. The measurements showed that the range of air velocities passing through the heat exchanger varied from 0.5 ms-1 to 3.0 ms-1, with the integrated average of the measurements being 1.75 ms-1. The PIV data was used to generate a map of the air flow distribution through the heat exchanger, which served as the basis for refrigerant circuitry optimization.

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