PRECISION COOLING SINCE 1990

+33 (0)4 37 43 20 00

info@a2p.eu

Free cooling according to A2P

Free cooling consists of producing cold water using the frigories existing in the ambient air, when the air temperature is lower than the desired water temperature. This free energy provides substantial savings. The use of free cooling optimises the cost of producing chilled water and drastically increases a cooling plant’s energy efficiency.

Technically, when the outside temperature allows it, cold water is produced with an air/ water heat exchange device called a thermoconvector or dry cooler. The air displaced by helical fans passes through the heat exchange batteries and transmits frigories to the water circulating through thin pipes.

Many manufacturers offer this option, either by integrating a standard dry cooler directly into a standard cooling module or by offering a chiller equipped with a double circuit condenser, one for the refrigerant fluid, the other to cool the water directly with cold air.

Without any flexibility on the option of “boosting” the cooling capacity available both in mechanical cooling (cooling using a compressor) and free cooling (cooling using ambient air), these standard solutions do not solve the problem of finding an economical and easily extendible process cooling supply in the long term.

A2P offers simple, original and intelligent configurations, dedicated to diverse, specific situations that optimise both free cooling and mechanical cooling. Our modular technology can meet our customers’ needs without overinvestment in power and while maintaining flexibility in the plant’s scalability. (REFERENCE 3.1)

Free cooling device RTS1

In the case of a plant based on a single water circuit, this RTS1 configuration offers very low operating costs thanks to a system that automatically optimises energy savings. The selected configuration proposes production of cold water based on two seasons.

 

Cold season:

As soon as the ambient air temperature is 3°C lower than the temperature of the water in the return lines, the thermoconvector gradually relieves the chiller(s), until it is completely replaced, if the ambient air temperature is 5°C lower than the set temperature. For example: If the set temperature is at 15°C with a return water temperature of 20°C, the thermoconvector will start operation as soon as the air temperature is equal to or lower than 17°C and will completely replace the chiller(s) as soon as the air temperature reaches 10°C. The chiller(s) stop(s).

 

Warm season:

Cold water is exclusively produced using the chiller(s). The thermoconvector is completely shut down.

The management of this plant and the changeover between the RTS1 cooling modes is done entirely automatically, thanks to a microprocessor connected to different probes that are part of the plant. The changeover between the thermoconvector and the chiller(s) is progressive. The chiller’s pump never stops and ensures process circulation.

Free cooling device RTS3

In the case of a closed, double-circuit installation, for example at two different temperatures of 15°C and 30°C, free cooling can be done, subject to certain conditions, with no greater investment than a set of servo valves and a slight modification of the piping (creation of a mixing bottle).

This solution offers very low operating costs thanks to a system that automatically optimises energy savings. The configuration chosen in a closed double circuit (e.g. tools at 15°C and hydraulic at 30°C), includes one (or more) thermoconvector(s) which play(s) a triple role:

  1. Completely replace chillers (producing water at 15°C) during times of the year when the ambient temperature is equal to or lower than the set temperature by -2°C, i.e. ≤ 13°C if the set temperature is at 15°C.
  2. Partially replace the chillers (producing water at 15°C) during times of the year when the air temperature sways between 13 and 18°C.
  3. Complete the action of the thermoconvectors assigned to the hydraulic circuit (30°C) in summer, in case of high heat.

 

The management of this plant and the changeover between the different cooling modes will be done entirely automatically, thanks to a microprocessor connected to different probes and valves that are part of the plant.

Free cooling device RTS4

This solution offers very low operating costs thanks to a system that automatically optimises energy savings for a plant operating on the basis of a closed double circuit: one circuit is assigned to a high temperature (e.g. hydraulic circuit at 30°C), the other to a low temperature (e.g. tools at 15°C).

The selected configuration proposes a production of cold water based on two seasons:

 

Cold season:

The low temperature is exclusively produced using thermoconvector(s). Only one temperature (low) is assigned to both circuits. The system switches to this mode as soon as the ambient air temperature is 5°C lower than the set temperature. The chiller(s) shut down completely.

 

Warm season:

Low temperature is produced using one (or more) chiller(s), high temperature using the thermoconvector(s).

The management of this plant and the changeover between the two cooling modes will be done entirely automatically, thanks to a microprocessor connected to different probes and valves that are part of the plant. This is a “firm” (non-progressive) changeover between the chiller(s) and the thermoconvector(s).

 

 

In conclusion

The A2P free cooling options are very powerful, scalable, eco-responsible and extremely economical: to give you an idea of the energy yields obtained through free cooling, refer to the “commitment to energy-efficiency” section.

As a general rule, free cooling works 60 to 70% of the time, although its role will strongly depend on the desired water temperature and climate.

The operation of free cooling is very simple. The user does not have to do anything: the optimisation is done automatically according to the air temperature, often several times a day, in order to take advantage of the smallest favourable air temperature variation.

These configurations are flexible and versatile. They can be modified and modulated separately, thanks to the modularity of the equipment that makes up the system.

There are configurations to optimise free cooling other than the RTS1, RTS3 and RTS4 options.

Free cooling solutions are much more extensive at A2P thanks to:

  • The performance of the A2P thermoconvectors which, far superior to that of standard dry coolers, allows higher energy savings (achieved without using an adiabatic system).
  • The possibility, thanks to modularity, to extend the power to be removed separately on the mechanical cooling part (chiller) and the dry cooling part (thermoconvector), which gives A2P free cooling total flexibility, setting us apart from our competitors.