AN-92-02-4 -- Water-Heating Energy Savings in Commercial Laundries PDF

Describes a heat recovery system to reclaim energy from the exhaust products of commercial-sized laundry dryers to preheat the water used by the washing machines, which has been designed, built and installed at a test site. The system uses two separate methods to reclaim heat and consists of a passive and active loop, each connected to a separate storage. The passive loop circulates water from the upstream storage directly through two sets of finless coils placed within the heat stream. Concurrently, the active loop circulates water from the downstream storage through the condenser section of a 5.kW heat pump that collects energy using an evaporator with large fin spacing. States that a computerised monitoring package has given preliminary results that indicate the passive and active loops supply approximately 35% and 25% respectively of the daily water-heating energy, while the electric resistance heaters used as back-up provide the remainder. Overall hot water storage and distribution losses have been minimised to less than 3%. Further analysis, using input and output energy values, showed that over the data collection period, average daily energy savings of 128 kWh, or 50% of the hot water consumption of the laundry, were achieved.

KEYWORDS: Laundries, heat recovery, water heating, preheating, commercial