Technical Field

The present invention relates to a method and a device for obtaining reserve time for a cooling system for cooling e.g. equipment for telecommunications installed in rooms.

Background

Equipment for telecommunication installed in rooms, during operation generates a considerable amount of heat energy. This occurs continuously and the temperatures around the equipment have to be maintained within certain limits . Particularly important is that a specified maximum temperature must not be exceeded. In order to achieve this temperature regulation, usually mechanical cooling systems e.g. compressor operated evaporation systems are used. In those the warm indoor air passes an evaporator and is cooled. Thereafter the cooled air is recirculated to the room. The continous heat generation requires continuous cooling.

In case of failure of e.g. a compressor cooling system some kind of reserve system has to be activated and provide cooling of the indoor air. One method to obtain reserve cooling is to provide cool liquid in a tank. At failure of the compressor cooling system, cold liquid is pumped from said tank to an air cooler in which the indoor air is cooled and is then pumped back to the tank again. This system however, can operate only a limited time since the liquid in the tank gradually becomes warmer. Therefore a system for obtaining reserve time for cooling indoor air is discussed.

Statement of invention

In order to obtain reserve time for an air cooling system by a reserve time system having a secured low level of the liquid temperature, an evaporator of the air cooling system has been provided with a liquid circuit connected to a liquid tank. The liquid is continuously circulated through the evaporator provided with the liquid circuit, where the liquid is cooled by the refrigerant of the air cooling system, simultaneously as the indoor air is cooled by the same evaporator. The continuus cooling and circulation of the liquid in the tank will secure that there all the time will be as cold liquid as possible available when the main cooling system is out of function.

At failure of the air cooling system the liquid is circulated by a liquid pump from the tank through the evaporator provided with the liquid circuit thereby cooling the warm indoor air. The heated liquid is returned to the tank. When the air cooling system functions again it will start to charge the tank with cold water.

Description of drawings

Fig. 1 illustrates a cooling system for cooling air by a reserve time according to the invention,

Fig. 2 illustrates a system for controlling and governing the cooling system having a reserve time system according to the invention.

Description of an embodiment

In Fig. 1 is in principle illustrated how a cooling system is provided with a reserve time system. The cooling system

includes: a condenser 1, an evaporator 2 provided with a liquid circuit 2b, a condenser blower 3, an evaporator blower 4, a compressor 5 and an expansion valve 8. The refrigerant circuit 9 is indicated by thin lines. The condenser 1 and the condenser blower 3 are located outdoors 11. The other equipment is located indoors 12. The reserve time system includes a liquid pump 6, a liquid tank in a liquid circuit 10 and the liquid circuit 2b in the evaporator 2. The liquid circuits 2b and 10 are indicated by thick lines. The cooling system with air cools a room containing e.g. telecommunication equipment. The reserve time is obtained in that cold liquid from the tank 7 is filled with cold liquid is pumped by the pump 6 and is brought to circulate through the liquid circuit 2b of the evaporator 2, whereby the air can be cooled and be returned back to the room after cooling.

The liquid in the tank is all the time circulated through the evaporator having the liquid circuit, in which it is cooled by the cooling system of the compressor. Simultaneously the indoor air is cooled by the same evaporator. The continuous cooling and circulation of liquid to the tank secures that there always will be as cool liquid as possible available if there would occur break downs in the compressor system. At failure of the compressor system, liquid from the tank will circulate through the evaporator having the liquid circuit and thereby cool the warm indoor air with or without the evaporator blower in operation. The heated liquid is returned to the tank. When the compressor system functions again, the system starts to charge the tank with cold water. At eventual failure of the power net or the

like, the liquid pump and the evaporator blower are driven from a battery through an inverter.

In Fig. 2 a system for controlling and governing the cooling system with the reserve time system is schematically illustrated. Measure signals from temperature sensors 13, 14 in the condenser and the evaporator with the liquid circuit, respectively are transmitted to the controlling and governing system 15 of the cooling system. With the controlling and governing system 15 the reserve time system can be connected at break-down of the cooling system. An external governing unit 16 is provided for power supply to the systems for their operation.