Water Cooling | Heat recovery

Article

Water cooling

15. November 2022

We experience an increased interest in a system-based approach to freezers/refrigerators as well as removing heat and saving energy by using the excess heat elsewhere in the facility.

System-based cooling

Customers often have rooms or areas dedicated to storage of temperature sensitive items. Our experience in supporting the market has shown that refrigerators and freezers are often placed in confined small areas or rooms. Electrical equipment in a confined space means heat leading to a poor working environment for the employees and the increasing ambient temperature results in a compounding negative effect on the operation of the cabinets.

The past couple of years, we have experienced an increased interest in a more system-based approach to freezers and refrigerators as well as removing heat and saving energy by using the excess heat elsewhere in the facility. This article explains the pros and cons of both air-cooling and especially water-based cooling – a cooling method that can be an opportunity to have a more sustainable approach to energy recovery, work environment and storage conditions for your temperature sensitive items.

The conventional system – Air cooled

The refrigeration system in a conventional refrigerators and freezers typically uses fan that facilitates the transfer of the heat energy from the condenser to the ambient air. It is a traditional and secure way of cooling the components.

Figure 1 shows a traditional refrigeration system, where ambient air cools the condenser and compressor. The heated air flows into the surroundings.

The ambient air is channelled through the system (see figure 1), moving the heat away and transferring the heat out and into the surroundings. This solution is a simple, flexible, and self-containing plug-and-play system, which can be put into operation and moved at a moment’s notice.

Figure 2: Traditional cooling principle.

This theoretical drawing shows the principle of traditional cooling; Electrical energy is supplied to the cabinet to energise the refrigeration system. The refrigeration system converts electrical energy into mechanical energy inside the compressor, transferring energy between the inside of the refrigerator or freezer and the ambient air, thereby cooling inside and expelling heat to ambient. Since heat is the main bi-product of operation, a refrigerator or freezer will have effect on the temperature in the room.

The illustration above is a stand-alone example, as other factors like; room size, doors, windows, sunlight, ventilation system, other electrical appliances etc., also affect the ambient conditions.

Advantages of air-cooling

Simple, flexible plug-and-play system
Easy to service
Good standalone solution

Disadvantages of air-cooling

Heat emission to storage room
Noise emission
If several cabinets in one room, potential of negative effect on working conditions due to increase in ambient temperature.

Using water cooling to lower ambient temperature

A water-cooled refrigeration system is especially well-suited for a storage area with several refrigerators and freezers and the solution has several advantages. Besides the direct effect of improved working conditions because of lower temperature in the working areas, the solution also presents a positive impact on the operation of the cabinets themselves as the added energy (heat) is transported out of the room, putting less strain on the cabinets. The major advantage of being able to move the excess heat elsewhere in the facility, is the potential of saving both energy and lowering the temperature.

Figure 3: The compressor compartment seen from the front. The heat exchanger is mounted on the right side. Between the compressor and the electrical terminal box is space enough for tubes, hoses and etc.

In practical terms, water cooling entails replacing the air-cooled condenser with a water-cooled condenser and inlet valve. The water-cooled condenser requires a connection to a process water system that facilitates heat transferring to the water. The process will then be led away from the room and used elsewhere.

Figure 4: Electrical energy converted to heat energy - absorbed into water and carried out of storage room.

In figure 4, we illustrate the process-water system cool the condenser, but instead of leading all excess heat into the ambient, the cooling water absorbs the heat and the energy from the refrigerant and 90% of the excess heat is transported out of the storage, making it possible to reuse the heat elsewhere in the building. This means; by removing the accumulated energy (heat) from condenser/cabinet, heat emission in the storage room is reduced to an absolutely minimum and 90% of the excess heat can be recovered and used for e.g.:

Hot water
Floor heating
Room heating in general

Recovering accumulated energy for heating applications can mean a massive energy saving potential. Luckily, there is a great focus from both industries and governments to save energy and minimise global warming and we see an increase in customers asking for consultancy in energy optimisation. The investment in a water-refrigeration system for heat recovery can be substantial short-term, however, all electrical equipment creates excess heat that can be recovered and used elsewhere, saving both energy and economy long-term.

Advantages of a water-based refrigeration system

Better working conditions for employees
90 % of excess heat can be used for other heating applications in the building
Energy and budget savings
Possibility of having several cabinets in a confined space with low effect on ambient temperature
Better operation of the cabinets due to of optimum operating conditions
No need for dedicated HVAC system

Requirements: Water-cooled refrigeration system

The water-cooled refrigeration system requires water supply, piping and connection to the overall process water system.

Many hospitals, laboratories or factories have these systems in place already, and then it is matter of sizing and connecting our cabinets in the best possible way. We will be glad to advise on your specific solution. Reach out and we will be glad to assist.

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