Combo air conditioner solution for outdoor cabinet
The combo air conditioner solution idea came from an application case study of China Unicom’s outdoor cabinet roll-out in 2008. They designed one compressor air conditioner and one heat exchanger unit for each outdoor cabinet as the cooling solution. The reason is the cabinet need a compressor cooling system in summer season to ensure the inner temperature under control at the level lower than ambient. But the operator would like lower power consumption in other seasons and the night time, while the ambient temperature is low enough to use heat exchanger solution. Envicool provided both of the air conditioner and heat exchanger in this project and customized the co-operating control function between them. Envicool engineers get the inspiration from this case and invented the combo air conditioner with heat exchanger, later using heat pipe (thermosiphon) replacing the heat exchanger to get a better efficiency.
This demand is quite popular in north regions, when the heat load inside the cabinet is getting bigger. An active cooling system (like compressor cooling) is necessary during the hot seasons, while a passive cooling (like fan system or heat exchanging) has the enough capability with the advantage of low power consumption. The green site cooling solution is pursuing the power consumption as low as possible to get better Capex and Opex results. The combo air conditioner solution is the best solution to meet the cooling and efficiency requirement in the outdoor cabinet applications.
By sharing the fans and controller, the Capex of cooling system is controlled under a reasonable level. In structure design’s point of view, the installation space for cooling unit is almost the same as before. The two cooling systems are working as the backup for each other due to the separated AC power and DC power. When ambient temperature is 10 degree lower than the targeted inner temperature, the heat pipe system could provide the enough cooling capacity only with two fans’ power consumption. All the power consumption for compressor has been saved. For this situation, the EER (Energy Efficiency Ratio) could be as high as 11.0, comparing to the EER around 2.5 for the pure AC-powered compressor air conditioners. The same effect is happening in the night time, for example in the site at desert area, while the ambient temperature varies in a quite wide range.
By the time, a new version of combo air conditioner is launching to the market configuring with the DC compressor system and heat pipe. Benefiting from the high efficiency compressor cooling system and the natural cool resource utilizing heat pipe system, the general power consumption for the pure DC powered combo system is in an extremely low level for the all seasons.