Refrigeration and Air Conditioning 3 E Part 2 potx

... contributes CO 2 emission to the atmosphere. The choice of refrigerant is therefore about the efficiency of the refrigerant and the efficiency of the refrigeration system. The less the amount of energy ... copper. This chapter is about the new refrigerants and the new attitude needed in design, maintenance and servicing of refrigeration equipment. 3. 2 Ideal properties for a re...

Ngày tải lên: 12/08/2014, 00:20

... 2 kW) Refrigeration and Air- Conditioning 26 Air- conditioning load estimation 2 63 27 Air movement 2 73 28 Air- conditioning methods 29 7 29 Dehumidifiers and air drying 31 6 30 Heat pumps. Heat recovery ... recovery 32 0 31 Control systems 32 4 32 Commissioning 33 3 33 Operation. Maintenance. Service. Fault-finding. Training 33 8 34 Efficiency and...

Ngày tải lên: 12/08/2014, 00:20

... (kW) 25 6 24 9 24 2 23 4 22 6 21 8 Compressor power (kW) 41 43 46 49 51 53 —— —— —— —— —— —— Condenser load (kW) 29 7 29 2 28 8 2 83 27 7 27 1 Example 6 .2 A condenser manufacturer gives a ‘heat rejection capacity ... covered by the provisions of BS.4 434 :1980 and require safety pressure relief devices as outlined in Section 6.10. In cases where there is no shut-off valve b...

Ngày tải lên: 12/08/2014, 00:20

... permit their use elsewhere. Table 10 .2, based on the tentative temperature differences of 15 K and 12 K 122 Refrigeration and Air- Conditioning plant will not be operated at its best efficiency. ... and shorten the working life. 11.11 Site pressure safety tests Site-erected pipework, once complete, must be pressure tested for safety and freedom from leaks. Pressures will be...

Ngày tải lên: 12/08/2014, 00:20

... provide an insulated and refrigerated enclosure suitable for the handling and storage of perishable goods, at some predetermined temperature. The shape and size of the cold store will depend on: 1. ... a eutectic solution, and these are frozen down by placing these elements in the domestic deep-freeze cabinet. Once frozen, they can be used in picnic baskets, etc., for the short-term s...

Ngày tải lên: 12/08/2014, 00:20

... hygiene, or the cheese will be damaged. Some cheeses can be frozen for long-term storage, but must then be allowed to thaw out gradually and complete their ripening before release to the market. Other ... and the sheet material skins may be flat or profiled. When the panels are manufactured the mixture is injected between the inner and outer skins and expands to the thickness required...

Ngày tải lên: 12/08/2014, 00:20

... down to 53 1.04 – 20 ice cream 2. 95 – 6 21 0 1. 63 cheese 2. 1 – 13 125 1 .3 Dried fruits 1.8 – 2 Eggs, shell 3. 05 – 2. 2 22 0 1.67 Fish, white 3. 55 – 2. 2 27 0 1.86 blue 2. 9 – 2. 2 21 0 1. 63 Meats, bacon ... estimation 21 5 ∆T a = temperature decrease above freezing h l = latent heat of freezing c b = specific heat capacity below freezing ∆T b = temperature decreas...

Ngày tải lên: 12/08/2014, 00:20

... (kJ/kg) 24 4 Refrigeration and Air- Conditioning will take place and the water will draw its latent heat from the air, reducing the sensible heat and therefore the dry bulb temperature of the air (Figure 24 .4). Example ... factor is therefore one of wet bulb rather than dry bulb temperature, and the closer the upper limits are approached, the less heat can be rejected and...

Ngày tải lên: 12/08/2014, 00:20

... 537 27 5 44 39 35 36 2 22 Sept. and 10 am 34 51 35 7 524 38 0 54 46 40 477 and 22 Sept. 11 am 35 54 1 82 4 53 4 42 161 49 42 544 22 March 12 noon 35 53 71 32 7 467 32 7 71 53 565 North latitude 1 pm 35 ... will be the velocity pressure. Figure 27 .2 Vertical and inclined manometers Figure 27 .3 Pitot tube Sensitive and accurate manometers are required to m...

Ngày tải lên: 12/08/2014, 00:20

... possible refrigerant leaks. Steam drives have also been used. The economics of the heat pump are dependent on the relative costs of the drive power and heat energy from other sources. In the UK, where ... refrigerant in a cooling system is reversed, the heat exchanger which was the evaporator becomes the condenser and vice versa (see Figures 9.4b and 28 .11) and the flow of energy is...

Ngày tải lên: 12/08/2014, 00:20