Free cooling

Refrigeration units modified for free cooling do not include the hq-uid-refrigerant pump and cooler spray header nozzles. Without the cooler refrigerant agitation for improved heat transfer, this arrangement allows up to about 20 percent of rated capacity. Expected capacities for both tnermocycle and free cooling are indicated in Fig. 12-21. 

In operating a coohng tower in the thermocycle or free-cooling mode, some precautions are necessary to minimize icing problems. These include fan reversals to circulate air down through the tower inlet louvers, proper water distribution, constant water flow over the tower, heat tracing of lines such as makeup lines as required, and maximum loading per tower cell. 

Combined thermal and multizone models are needed for problems such as thermal comfort analysis in naturally ventilated buildings, determination of heat-removal capacity by natural ventilation, design and evaluation of free cooling by nighttime ventilation. This is outlined in more detail in Section 11.5. 

Benzene Triozonide (Ozobenzene, Benzoltriozonid in Ger). CjjH CU (probable structure given by Beilstein, Ref 1) white, amorph, si volatile solid sol in benz, insol in ale, eth, chlf, CS2 and ligroin. Prepd by Renard (Ref 2) and Harries et al (Refs 3 4) by passing ozone thru pure benz (thiophene free), cooled to 5—10°... 

Abstract. Newly established residential area in Vastra Hamnen (West Harbour) in the city of Malmo uses Aquifer Thermal Energy Storage (ATES) as part of the district heating and cooling system. ATES system has 5 warm and 5 cold wells that are 70-80 m deep. Cold from the nearby sea (Oresund) and water cold from heat pump is stored from winter to summer. The purpose of the system is to deliver free cooling to district cooling system at a temperature level below +6-8 °C. Operational experiences and economic aspects are discussed. 

The purpose with the Aquifer Storage is to deliver basic free cooling to the DC system at a temperature level below +6-8 °C. This is achieved by storage of evaporator cold at +4.5 °C and cold from the seawater at temperatures below +4 °C. The warm side of the system works with temperatures between +13 -and 15 °C. The maximum flow rate is for legal reasons limited to 32.51/s (117 m3/h). 

The summer season 2002 the storage was delivering cold approx, half of the designed amount. The reason for the less free cooling production was that the heat pump, from which waste cold should be stored during the winter, was shut down because of technical problems. Hence, the only cold stored in the aquifer came from the surface water. 

Keywords PCM phase change latent heat melting heat storage cold storage comfort requirements space heating space cooling, free cooling... 

Figure 198. Free cooling by storing coolness from the night and use it for space coohng in daytime (left) and design of Climators CoolDeck (right)...

Active systems that use the cold of the night air are usually called free cooling systems. 

Case study Biocide-free cooling lubricants and minimum quantity cooling lubrication ... 

NOTE Free cooling from exhaust steam means, in reality, a low cost power source, and is not the same as the free cooling principle employed during winter months, when chilled or condenser water is circulated over the cooling tower without the necessity of switching on the tower fans. 

Does the sugar refinery shut down during the winter Does the textile plant operate a free-cooling strategy during the winter in order to save money ... 

This mechanical refrigeration system can be automatically reconfigured to operate in any of the four modes including the three free cooling configurations, which are listed in Table 2.14. 

Equipment Mode 1 (Mechanical refrigeration) Mode 2 (Vapor migration based indirect free cooling) Mode 3 (Indirect free cooling by the use of heat exchanger) Mode 4 (Direct free cooling with full filtering)... 

The controls of both the "open" and the "closed" direct systems are very simple, because they consist of only a differential thermostat and a pump. The differential thermostat starts and stops a constant-speed pump whenever the detected temperature difference is favorable. In more sophisticated systems, it adjusts the speed of variable-speed pumps (or selects a small or a larger constant-speed pump for operation). What AT is "favorable" is a function of not only the "availability" of free cooling or free heating, but also of the cost of pump operation, which increases the AT thermostat set point. 

Free-cooled, 1/16 Inch specimens with relative crystallinity of 65%-68%, tested using ASTM D4894/4895. 

Paleotopography. Apatite He ages are sensitive to temperatures found at depths of between 1 and 3 km within the Earth s crust (Fig. 4). At these depths the crustal temperature field is strongly influenced by the position of the free cooling surface, such... 

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