Design of a heating, ventilating and air-conditioning system that utilizes multiple condensing units in the refrigeration circuit

Abstract

The heating, ventilating and air conditioning system performs a critical role in pharmaceutical products manufacturing by majorly providing thermal comfort and acceptable indoor air quality, conditions required for the production. efficacy and stability of the products. What motivated this study was downtime the HV AC system is likely to be subjected to. An HV AC system, just like any :functional system is bound to be subjected to downtime, which is majorly because of the refrigeration loop. This downtime problem was approached by using the action research methodology, where after problem identification, steps were taken to design and model an HV AC system that not only eliminates the chilled water loop but also incorporates multiple condensing units of the same capacity in the refrigeration loop. This was done with the idea of providing backup for the major components of the refrigeration loop i.e the condensing units to minimize downtime. However, this is no mean feat owing to the fact that assembling refrigerant compressors in series is not an option since these compress a vapor into a liquid and, should a liquid be introduced into the compressor, one runs the obvious risk of damaging the compressor, which is expensive, and time consuming to replace. Despite a new design of the HV AC refrigeration loop being developed. care was taken to ensure that the modified system does not lose its characteristics that enable it to perform the other :functions of an HV AC system. The physical model designed, constructed and installed answered the research question that multiple condensing units can be incorporated on a single refrigeration circuit. Validation of the installed system proved that the system is capable of attaining the thermal comfort requirements required for pharmaceutical products manufacturing. Lastly, a comparison with a conventionally designed HV AC system was made and in a four month time period, the conventional HV AC system had experienced down time totaling to 24 hours as a result of failure of components in the chilled water loop. This is dangerous to the products as it poses a risk of compromising production, efficacy and stability of the manufactured products. The new design gives HV AC design engineers an edge while designing HV AC systems for minimal