1. Thermal Control Products
For Telecom enclosures and shelters
Application Guide
IT Enclosure Systems

2. About us
We are a supplier of reliable, low-cost, energy-efficient climate control solutions with precise thermal and humidity control for enclosures in telecommunication, IT Industry and automation applications. Huarui Cooling Products are specifically designed for cooling electronic temperature sensitive equipment in challenging environmental conditions.
We can not change the weather, but when it comes to controlling the temperature and relative humidity, under the most extreme conditions, HUARUI thermal control is globally acknowledged as one of the world’s leading experts.
IT Enclosure Systems

3. Selecting a cooling solution
HuaRui
Selecting a cooling solution
Heat could affect or damage the electronics inside a cabinet. Some of this heat is dissipated through the cabinet walls. Depending on the size of the cabinet and the ambient temperature, this way of heat removal could be adequate for the application.
Another way of removing heat from a cabinet is by using Fresh Air Cooling. This could be accomplished with a combination of fans and filters. This type of thermal management solution may be used when the installation site is relatively clean and cool such as an office building or inside a cool telecom shelter.
When the electronics inside a cabinet need to be protected from contaminating elements, the recommended solution is to use a Closed-loop cooling system like a heat exchanger, an air conditioner or a thermo electronic cooler (Peltier). This is what is usually used in harsh environments such as outdoor applications in telecom BTS, oil rigs, substations and/or when temperature and humidity levels inside the enclosure are critical.
IT Enclosure Systems

4. Closed-loop Cooling
In a closed-loop cooling system the cabinet is sealed from the outside and therefore the components are protected from elements of the exterior environment.
There are two separated air cycles:
The internal cycle which forces the hot air through a cooling core and
the external cycle which forces the hot air out of the cooler.
IT Enclosure Systems

5. Cooling technologies
We provide three types of climate control for enclosures
Passive Cooling: Heat Exchanger (HEX)
Active Cooling: Air Conditioners (AC)
Active Cooling: Thermal Electronic Cooler (TEC) Peltier
IT Enclosure Systems

6. Heat Exchanger
Heat exchangers can be used when the components inside the cabinet can operate at a temperature above outside air temperature.
The temperature inside the cabinet will be slightly above the outside air temperature.
The heat exchanger keeps the air circulating inside the cabinet which does not allow hot spots to form.
IT Enclosure Systems

7. Air conditioner
Air conditioners should be used when the temperature in the enclosure must be maintained at or below outside air temperature.
Air conditioners will remove humidity from the cabinet.
The AC unit keeps the air circulating inside the cabinet which does not allow hot spots to form.
IT Enclosure Systems

8. Thermal Electronic Cooler - Peltier
TEC modules are solid-state heat pumps that operate on the Peltier effect, which have no compressor, no refrigerant and require little or no maintenance and have a long life operation.
Provides below outside air temperature cooling.
Fast response with very accurate temperature control.
Small size, light weight and suitable for compact enclosures.
IT Enclosure Systems

9. Choosing Passive vs. Active cooling
Temperature inside the enclosure
Heat Exchanger
Air Conditioner
Peltier
Must be lower or equal to outside temperature - X
Could be slightly above outside temperature
Humidity inside the cabinet
Heat Exchanger
Air Conditioner
Peltier
Must be kept low - X
IT Enclosure Systems

10. Installation guidelines
The installation site and the positioning of the cooling unit must be selected in such a way as to ensure good air circulation inside and outside the unit. Make sure that inlet air and outlet air are not obstructed. This is critical to maintain the best cooling efficiency.
Do not position the components inside the cabinet too close to the air conditioner outlet in order to maintain an optimal cooling airflow at all times. Try to arrange the equipment inside the cabinet in order to ensure even air circulation. Do not direct the cool air directly to a warm air stream coming from an active electric device such a rectifier or inverter in order to prevent an air short-circuit condition.
The following examples will help avoid some of the pitfalls that could affect the performance of the thermal management system.
IT Enclosure Systems

11. Inside the cabinet
Poor arrangement inside the cabinet could cause the cool air to be returned to the return inlet (air short-circuit) without cooling the components
Air flow critical area
Cool air coming from the fan should be able to circulate inside the cabinet and around the components
IT Enclosure Systems

12. Inside the cabinet
A deflector in the return inlet helps to avoid air short-circuits
Air flow critical area
Air deflectors could help direct the cool air where is most needed
IT Enclosure Systems

13. Inside the cabinet Inside the cabinet installation
Air ducts help direct the exhaust hot air to the outside of the cabinet
Short-circuit is prevented
A duct directs the outside fresh air to the cooling unit air inlet
IT Enclosure Systems

14. Outside the cabinet Louver design
This is a good design where hot air being exhausted from the cooling unit does not mix with fresh air intake
This design presents potential problems: Air exhaust from the unit could be mix and be reabsorbed by the air intake.
Air exhaust
Another problem:
The louver angle could allow rain water and dust infiltration
Air intake
IT Enclosure Systems

15. Outside the cabinet Louver design
This design presents potential problems: Air exhaust is to close to air intake and hot air could be reabsorbed by the cooling unit.
Air exhaust
Air intake
IT Enclosure Systems

16. Poor design: Louvers too small for adequate air exhaust
Outside the cabinet
Louver design
A good louver design will allow maximum air-flow to minimize air drop pressure and reduce noise
Poor design: Louvers too small for adequate air exhaust
IT Enclosure Systems

17. Outside the cabinet Louver design
When using an additional cowling, care has to be taken to avoid reducing air-flow.
Exhaust opening of the heat exchanger
Louver area on cowling should be at least 50% larger than HEX opening
IT Enclosure Systems

18. Filter or not?
It is not recommended to install an air filter on Huarui heat exchangers.
The core material is made of epoxy coated aluminum with fins spaced at 3-4 mm. This corrosion free surface coating prevents accumulation of dust and improves efficiency.
Air filters might be necessary with air conditioners and Peltier units depending on the environmental conditions of the site. (Dust, sand, debris, insects)
Standard units have no filters.
When installing a filter make sure it has easy access for maintenance.
IT Enclosure Systems

19. Noise emission
Modern environmental requirements demand low noise levels for telecommunication cabinet products, especially when located in offices or urban areas. The spaces available are limited, and the power and electronics packaging density are increasing.
The main noise source of telecommunication cabinets is the cooling fan, and the fan noise interacts with the cabinet structure and cavities in a complicated way. If the fan noise can be decreased, the total noise will also decrease. The use of sound absorbing materials like foam and a labyrinth air path can help reduce the overall noise level.
If your power source is native 48VDC (or -48VDC) as part of a telecom or off-grid solar application, DC air conditioners are your most efficient cooling choice. DC brushless fan motors can greatly reduce energy consumption, and run with super low noise.
IT Enclosure Systems

20. HuaRui Thermal control Technology
Suzhou Huarui Thermal Control Technology Co.,Ltd
Plant A2, No.2, Tian'e Dang Road, Wuzhong District,
Suzhou, Jiangsu province,
CHINA
Tel: /
Ext: 819 (For overseas sales )
Fax:
web site:
IT Enclosure Systems
8 Chemin Abri Du Bois
Chelsea, Ottawa-Gatineau
Quebec – J9B-1S7
CANADA
Tel:
Fax:
web site:
IT Enclosure Systems