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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

HuaRui Thermal control Technology Suzhou Huarui Thermal Control Technology Co.,Ltd Plant A2, No.2, Tian'e Dang Road, Wuzhong District, Suzhou, Jiangsu province, 215104 CHINA Tel: +86 512 66570331/66570332 Ext: 819 (For overseas sales ) Fax: +86 512 68792690 e-mail: info@huaruicooling.com web site: www.hauruicooling.com IT Enclosure Systems 8 Chemin Abri Du Bois Chelsea, Ottawa-Gatineau Quebec – J9B-1S7 CANADA Tel: +1-819-866-3020 Fax: +1-819-483-1630 e-mail: contact@itenclosuresystems.com web site: www.itenclosuresystems.com IT Enclosure Systems