September/October 2020

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comfortec figure rental comfortec hockey rental sharpen your EDGE As for the "grade" of heat available, that refers to the temperature of heat that can be recovered. In the case of all systems, except CO2, there are two grades to consider: superheat and condensing heat. HEAT IT UP The superheat is the high temperature heat that can be harnessed from most systems at temperatures above 120˚F. The heat recovery equipment installed to capture superheat only is commonly referred to as a desuperheater. The strength of recovery-by-desuperheater is the temperature of heat available often providing recovery above 110˚F. However, the portion of total heat rejected is only 10-20 per- cent depending on refrigerant installed. There is usually enough superheat to provide resurfacing water at a rate of about 100 gallons per hour when the rink is in operation. This makes the combination of a desuperheater in rink operations an ideal pairing for most rental schedules. What about the other 80-90% of the rejected heat? That heat can be reclaimed using a full condenser in which a state change in the refrigerant (gas to liquid) occurs. This is at a lower temperature (grade) of heat reclaim typically between 80˚F to 100˚F depending on both the equipment and the refrigerant installed. As for CO 2 based refrigeration systems, these operate "tran- scritical" much of the time due to outdoor ambient temperatures, and without getting into a lot of details, these have gas coolers as opposed to the type of condensers typically installed in ice rinks. CO 2 based systems recovery at multiple temperature regimes. Some energy is higher-grade (temperature) but additional energy is lower grade as compared with the discussion in this article. USICERINKS.COM SEPTEMBER.OCTOBER.2020 / 31 • Ice Rink Cold Floor HEAT RECOVERY DESIGN , Heat recovery is about capturing the heat expelled from the refrigeration system to use for other purposes in the facility. Examples (shown in red above) may include subsoil heating, snow melt pit, ice resurfacer hot water, domestic hot water preheat, comfort heating, radiant floor heat, dehumidifier, etc.

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