What do you have to think about when renting cooling?
Rental of cooling is relevant in many different scenarios. Whether it is a matter of urgent needs in the event of a sudden shutdown or a more planned operation, it is good to be aware that you can hire cooling from Energy Rent.
The team below has for many years helped our customers to maintain production, lower costs and deliver higher and higher quality.
When you are going to start renting cooling, there are several things you have to take care of. First, the cooling capacity must be determined, and here Energy Rent can help with the dimensioning.
The heat transfer fluid is a very important component. To be able to dimension the cooling machine correctly, and to be able to take out the correct pumps, you must have full control over the heat transfer fluid. Optimal cooling capacity is not enough if the flow is too low, or vice versa, show correct flow but wrong heat transfer fluid.
Correct dimensions of hoses and correctly dimensioned heat exchangers are also important.
In this article, we will discuss different ways to attack a project, as well as show how we can avoid potential problems.
Here you will find our coolingmachines for rent
Best practice when you rent cooling
In order to calculate the required effect, several factors must be taken into account. Among other things, it is useful here to have information about the desired temperature either in a room or on the ice water, the effect (if this has been calculated), flow, size of the room, and what material this consists of in order to estimate the u-value/insulation value. These are good indicators for calculating the power requirement.
Here, different applications will have different requirements and needs. For example, a data center or server room will often need a temperature of around 20 degrees to ensure favorable conditions for technical equipment, with associated humidity. A cold and freezer room will need equipment adapted to the low temperatures, as the ice water from the cooling machines will be -10, and lower, to ensure a room temperature of a couple of degrees and below.
For fridges and freezers, defrosting is also necessary to remove ice formations on the fans that deliver cold air into the room. Our mobile equipment is suitable for cooling rental for urgent and short-term needs. If you want to cool a tent or a hall, there will often be poor insulation values, therefore a high air volume will be preferable. You can recirculate air for a maximum cooling effect, or combine it with a fresh air supply.
For HVAC, there will often only be a need for ice water where the rest of the infrastructure is existing. Then you can rent cooling from us in the form of a cooling machine.
1. The refrigerator
The cooling machine is the very heart of the process. A refrigeration machine essentially consists of a compressor, evaporator, condenser, refrigerant, and expansion valve. It is the pressure and temperature difference that is used in a cold process.
Heat is absorbed from the surroundings via the evaporator, which maintains a lower pressure, and compresses the refrigerant up – and out into the condenser. The condenser emits the absorbed heat via higher pressure and temperature.
In the condenser, the gas changes to liquid, hence the name condenser. When all the gas has turned to liquid, you want to subcool the liquid a little before it hits the expansion valve. Above the expansion valve, the pressure drops, and the lower the pressure, the lower the temperature. The low pressure is generated by the suction side of the compressor.
Different types of cooling machines
There are many different ways to run the cold process. Basically, we are talking about air-to-air, air-to-water and water-to-water cooling machines. The terms say something about how we absorb and emit heat. For example, an air-to-air chiller has an air-cooled condenser and an air-cooled evaporator.
Consequently, an air-to-water will have an air-cooled condenser and water-cooled evaporator, also called an ice water machine. Cold water, or ice water, is then produced. What is a bit special about cooling machines is that the effect is stated nominally, which means for a given area.
Normally, the effect will be stated according to a given standard, for example. EuroVent. Then the effect is stated at 7/12C ice water and 35C ambient, i.e. nominal effect.
The challenge begins when we have a project where the customer needs 100kW of power at -10C ice water. Challenges can arise here if only a cooling machine with a 100kW nominal power is used.
Nominal or real cooling performance
A rule of thumb says that for every degree you lower the evaporation temperature, the effect drops by around 3%. This means that a 100kW cooling machine performs almost half at -10C ice water. It is important to dimension for the correct effect so that you both ensure enough effect, but also do not oversize and wear out the equipment in a short time. For example, starting and stopping considerably shorten the lifespan of the compressors/cooling machine and therefore it should handle the variation in real load.
In this situation, a cooling rental can be a good alternative so this uncertainty is not placed on you as a customer. We assist with both planning and adjustments, and we can easily change the machine if this is necessary.
Location of the cooling system
If you look at permanent cooling systems, the cooling machine itself is often not that big, but the accessories and pipes take up considerably more space. If you choose to place the cooling system indoors, you must preferably have dry coolers outdoors, or exchangers that alternate with another source, for example seawater. These are processes that take considerable time to design, manufacture, install and commission.
If the plant is critical to the operation, you will often want to test the plant before handing over with a load bank. Then a mobile load bank heating center can be a good alternative to rent to carry out this. One should also consider the need for redundancy for unforeseen stops in the plant and continue to operate the plant.
This is something we value ourselves, where we run redundancy on our facilities for customers as far as possible. Here, too, our machines KM170 are a cost-effective alternative with 2 independent cooling circuits and 4 compressors.
A mobile plant can be started quickly as the equipment arrives fully tested and ready for use. We also have all kinds of accessories such as flexible hoses, buffer tanks, pumps, shunts and much more for quick installation and operation.
Actually, in most cases we will be able to have operations within 24 hours of order!
2. The heat transfer fluid
As the name suggests, the heat transfer fluid must transfer heat. There are two places in the cooling process where heat is transferred; one in the evaporator and the other in the condenser.
It is important to have control over the heat transfer fluid to avoid operational problems and ensure the optimal effect. For example, PH, smell and color are good indicators of its condition. For permanent installations, it may be advisable to have an annual check, and to send the liquid to the lab for testing and any corrections in the inhibitor package can be made.
Bad liquid can lead to the corrosion of metal or gaskets or coatings in pipes and exchangers. This in turn leads to leaks, components that fail, and poor effect – and energy utilization.
We take the environment seriously
We at Energy Rent are concerned about the environment. In this connection, we use, as far as possible, environmentally friendly, highly efficient heat transfer fluid in all our rental projects. Here you can read more about the highly efficient heat transfer fluid Kilfrost GEO.
When we choose heat transfer fluid, this affects the cooling effect, pressure drop, pumps, etc. In order to have control over the dimensioning, we will always calculate the cooling effect and the pumps based on knowledge of what kind of heat transfer fluid we are going to use. If you are going to rent cooling from us, we will ask you for key information in order to deliver a system adapted to your needs.
3. Dimensioning of pumps
In a water-borne system, the circulation pumps play a central role in order for everything to work as intended. Necessary consideration of flow, the heat transfer fluid, correct adjustment, and resistance, which the pump must overcome, are key factors. The pump can be set up as on/off or controlled with, for example, a frequency converter.
We adapt the mobile cooling system to your existing system, and perform pressure drop calculations on both the temporary system and the customer system if we connect to this.
The correct information is important
Information such as pipe dimensions, lengths, valves, and other information is important to ensure a well-functioning system. Here we calculate flow and back pressure so that the effect matches the cooling machines. A cooling machine must have a constant flow, and must not, for example, be throttled with a shunt valve. This can be solved in several ways, with a buffer tank, heat exchanger or bypass.
Once you have gained an overview of the system as a whole and calculated pressure drop, a suitable pump must be chosen. A pump curve is used as a basis for selection, and one must also take into account the available power, space and delivery time. When adjusting, it will be absolutely central to ensure good ventilation of the system, to have good suction on the pump, and to hit as close to the pump curve as intended.
x meter with 4”, power required. Calculates flow and pressure drop and removes pump after this.
This pump is able to move approx. 18m3/h with a back pressure of 4 bar, while it is the most energy efficient with 35m3/h and 3 bar back pressure (40% ethylene glycol/60% water). In order to hit the desired operating parameter, tools such as frequency converters, valves, and manometers can be used.
If the system runs without noise or leaks, and at the calculated output, while achieving the desired result, then you are well on your way. The pump depends on good conditions such as positive suction pressure (often 1 bar) and the correct dimension of the pipe connected to the suction side of the pump. The pump curve is read with flow and pressure in correlation.
See our selection of rent pumps, and if you want to rent cooling get in touch
4. Dimensioning of heat exchangers
Heat exchangers are used in cooling systems to separate different media from each other and ensure good cooling. This can be water, glycol, seawater, refrigerants and much more. Heat exchangers are exposed to soiling as they act as a fine mesh filter in the system. Therefore, you should use a filter, clean the system well before use, and have control over the heat transfer fluid in the system.
It is very important to run the two sides against each other in countercurrents to ensure optimal transfer of the temperature. This gives the greatest possible transfer time with the greatest possible temperature difference. Heat exchangers vary in size, material, and effect according to the needs, and the smaller the temperature difference between the two media, the larger and more expensive the heat exchanger is needed.
Beware of low LMTD
For example, an LMTD of 2, i.e. a temperature difference between the liquid on side 1 and 2, of 2 degrees will be significantly smaller in size one if one wants an LMTD of 1 degree/kelvin.
Let’s show a simple calculation with a cooling system that runs a glycol mixture of 5/10 degrees into the heat exchanger, and on the other side wants water at 7/12 degrees.
This gives an LMTD of 2 degrees/Kelvin, and if, for example, you want an LMTD of 1 degree, then a rule of thumb is to double the area of the heat exchanger, and thus also the price.
Experts in temporary heat transfer
We have many years of experience with dimensioning and sales of permanent heat exchangers, in addition to experience with mobile heat exchangers for temporary use. This ensures that we can calculate systems and deliver a tailored mobile plant straight from our warehouse shelf. If you are going to rent cooling, we will go to great lengths to deliver the desired equipment and quality at the agreed time and price.
Delivery of accurate temperature requirements
If you want an exact temperature, as we experience for example with aquaculture/breeding facilities, it may be a good idea to run a shunt to achieve this. We have all the accessories that ensure fast operation in the plant; heat exchangers, flexible hoses, shunts, accumulator tanks, air handlers, dry coolers, expansion, pumps and much more.
Let us help you design the mobile cooling solution. We do this very quickly.
5. Service and maintenance
In a refrigeration plant, service is very important, which includes checking liquids, pumps, pipes, valves and refrigeration machines.
Ask us if you need a good service partner in your area. We have a wide network in Norway that can carry out this. In the event of planned or unplanned downtime, it can be beneficial to rent a temporary facility, Energy Rent will be happy to help you rent cooling for your project.
When it comes to the cooling machine, service and F-gas are necessary to ensure operation. Major repairs and replacements of components or machines may also be necessary, not to forget the various refrigerants that are being phased out and must be replaced by new types with better GWP (Global warming potential). Then you can rent cooling from us to ensure operation.
When it comes to Dry coolers and cooling/freezing coils these are exposed to dirt on the outside and inside of the coil/radiator. The outside must be washed with low pressure and kept clean, while inside it is the heat transfer fluid that must be kept under control to avoid leaks and power reduction.
Should a dry cooler break down and need to be replaced or repaired, renting a mobile dry cooler or cooling/freezing coil from Energy Rent can be helpful. New facilities should be thoroughly cleaned before commissioning to remove oil and metal residues from production. We can assist with chemical cleaning on both new and old facilities.
Our cooling equipment is ready for delivery and will, after a test and check, be sent straight to the car delivered to you at the agreed time. The cooling system can be sent in your own car for fast delivery, or as a combined load for the most reasonable shipping cost.
Tolerates tough treatment
The cooling machines and accessories are made for rough use. Most also for outdoor placement in weather and wind. Refrigeration equipment placed in frames and containers ensures simple, fast and safe moving of the equipment for both loading, unloading and outside the project during assembly. We have a wide selection of modular mobile cooling systems that ensure you have available equipment to rent cooling from us.
We transport refrigeration equipment throughout the Nordic region through our shipping partners, and can always deliver very quickly. Often the estimated delivery time is only the time spent on shipping from our warehouse to you. Our 24-hour helpline is there for you when you need immediate help.
7. Lease agreement
A rental agreement offers many advantages for you as a customer. It ensures fast delivery, access to a large selection of equipment, and gives you the opportunity to try out different types of equipment and power requirements. You don’t have to tie up capital in investments, but you pay ongoing rent that can be terminated whenever you wish after an agreed commitment.
In the event of a shutdown, we replace the equipment with another machine and ensure continued operation.
Are you going to expand production, have a large project, or move in the near future? Then renting cooling from Energy Rent could be a good solution for you.
Plus, you will get a professional team which got your back, and assists with technical preparation, assembly, and operation. The vast majority of our machines have remote monitoring with set-up alarms, and with a quick emergency response if an accident should occur. If you do not have suitable personnel, or wish to operate the facility yourself, we will also take care of this through an operating agreement.
Get in touch and we will adapt the cooling equipment to your needs.
Rent cooling from Energy Rent AS.