3.1.4.
Integration of refrigeration and HVAC
BEMP is to recover the waste heat from the refrigeration cycle and to maximise its use. Food retailers are able, under certain circumstances, to produce excess heat even after using the heat for space heating, which can be delivered to other parts of the same building or to other buildings.
Applicability
The measures should be taken into account for new or existing buildings of food retailers and the operation of these systems would have different results depending on different factors:
—
Building size and use
: large retailers' stores are usually not alone in their buildings. Therefore, the ‘neighbourhood’ (e.g. small shops in a shopping centre) is a potential consumer of the excess heat. As a general rule, a grocery store with a typical refrigeration load and an optimised envelope would recover enough energy to heat twice its own surface.
—
HVAC design and maintenance
: all the elements of the HVAC system should be correctly designed and maintained. Exhaust air heat recovery, on-demand control of ventilation with CO
2
sensors and monitoring of air tightness and indoor air quality are strongly recommended techniques.
—
The refrigeration load
: smaller shops offer more refrigerated goods per square metre of sales area and the efficiency in refrigeration is lower. In addition, the trend to increase the amount of refrigerated goods available is also important. The size of the shop does not influence the technical applicability of integrated approaches, but the cost-efficiency of the whole system is lower for small shops.
—
Climatic conditions
: in cold climates, the load for refrigeration is lower than for warmer regions. At the same time, the heat demand of northern European buildings is high, so the integration would depend on the quality of the building envelope. For the warmest climates, e.g. Mediterranean countries of Europe, the cooling demand can be very significant and the air tightness of the building can make the internal gains increase. An optimised ventilation design is, therefore, necessary. Mechanical cooling at night and variable indoor temperature (e.g. 21-26 °C) are also recommended techniques.
—
Ambient temperature
: in the integration of the refrigeration cycle, there is a limit to ambient temperature, which depends on the system design, where the waste heat generation rate is not enough to keep a comfortable temperature inside the buildings. An extra heating source may be needed but this, again, depends on the quality of the building envelope.
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Building ownership
: many shops are integrated in a residential or commercial building, which belongs to a third party. Better integration of heat recovery, therefore, must involve actual building owners.
This BEMP is applicable to any new and existing refrigeration system to be installed in new or renovated stores, being fully applicable to
small enterprises
(given the conditions above). Nevertheless, small companies may require outsourcing technical assistance.
Associated environmental performance indicators and benchmark of excellence