XL Chilled Water System - XL HYDRO-COOL
In 2010 XL installed 3 full chilled water systems at separate Heathrow Airport Terminals to cool XL Chilled Food Displays. This is a system where we have remote water chillers and this chilled water is what we use to cool the food displays.
In T4 Heathrow we have an L shape Serve Over display and 3 Multidecks running on a ‘ring main’ chilled water system.
( pictures above and below )
In operation we have found this system to be significantly more efficient than a conventional direct expansion refrigeration system.
The system uses standard water chillers and these chillers chill a glycol solution down to minus one or two degrees centigrade. This chilled water is then pumped through insulated pipe work to the displays. Each display, if it has several temperature zones, has its own manifold and from this manifold the chilled water is evenly distributed to the chillier coils in the display. These chiller coils are approximately four times the size of a conventional evaporator coil and this allows the chilled water at 0C in the chiller coils to chill the display down to a product temperature of 5C
The chilled water is at an almost static state in that it stays at a very constant temperature. This leads to an almost constant temperature in the display. This is achieved with absolutely no normal refrigeration controls .. no expansion valves , thermostats , solenoid valves or any other part that could fail in a normal display … each display is just the opposite of a radiator .. as simple as that.
The standard water chillers use a very small amount of conventional refrigerant ( at T4 1.8KG ) or if required one of the new more fashionable refrigerants, propane , CO2 etc .Unlike a lot of applications the very low amount of refrigerant in a standard chillier means that what ever refrigerant is used the system is totally safe and if a problem does occur in later years with one of these new refrigerants its only the standard chiller that has to be changed or modified .. not anything else. This is also very advantageous as it nicely avoids the most onerous parts the new F-Gas regulations where you have larger amounts of refrigerant.
The reason these systems are so good :-
We are using very large heat exchange surface areas .. so this is more efficient
The chiller only has to chill to -1 .. A relatively high temperature and so easy to achieve and energy efficient.
We have absolutely no DEFROSTS.. so if the temperature in the display never rises you do not have to do ‘more work’ to pull the temperature back down – a very big advantage. Having to defrost a display and then pull the temperature down again uses a large amount of energy and is very inefficient, especially as on some displays the defrost is by means of heaters !
As with no defrost we have no ice build up on an evaporator, therefore we have more consistent air flow.
Climate Change…The very minimum of refrigerant in the system… all the rest is a totally safe antifreeze solution. The system uses considerably less electricity.
Practically no product weight loss for unwrapped product as the high temperature of the chillier coils gives a very high humidity.
Some of the heat put out by the remote chillers could be recovered or ducted back into the building.. even more efficient
A very adaptable system… just like you can add a radiator or take a radiator out.. a chilled display in a system can be very easily taken out of a system of added where ever you like. And then simply connect up to the chilled water system.., simple plumbing
- Why we do not use CO2 as a refrigerant .. CO2
Why we do not use Hydo Carbons ( propane ) as a refrigerant Hydro Carbon
