Cooling, water costs

Cooling water costs tend to be low relative to the value of both fuel and electricity. The cost of cooling duty provided by cooling water is on the order of 1 percent that of the cost of power. For example, if power costs 0.07 kW h, then cooling water will typically cost 0.07 X 0.01/3600 = 0.19 x 10 kJ or 0.19 GJ L... 

Cooling water cost is reduced and total heat exchanger plus condenser surface may be reduced. 

Cooling water cost 0.005 S-kWtr1 Figure 23.56 Site marginal steam costs for the case study. 

At, = log-mean temperature-difference driving force over condenser, °F Hy = hours the condenser is operated per year, h/year Cw = cooling-water cost assumed as directly proportional to amount of water supplied, /lb... 

Cooling-water costs vary greatly, depending on the geographical location, water-treating problems, pumping costs, etc. (see Chap. 7). 

The variable costs for storage include the energy and cooling water costs both are a function of the desired level of pressurization, compressor efficiency, and electricity cost. 

The total capital cost must then be adjusted for depreciation to determine the annual capital cost using the CRT. The total cost of liquefied hydrogen storage is the sum of the liquefier, dewar, energy, and cooling water costs. 

Other costs may be considered, such as the cost for floor space for the system and the cost of maintenance. These may vary for individual situations and cannot be considered here. We may, however, consider the cooling water cost. Many of the tubes are water cooled, and the cost for the cooling water should be considered. The water requirements are directly proportional to the output power of the tube for example, a 6 kW magnetron at... 

The total bare-module cost for the column and its auxiliaries = 2,226,000 The annual heating steam cost for the reboiler is computed = 728,000/yr The annual cooling water cost for the two condensers = 84,000/yr The annual electricity cost for the reflux pump = 38,000/yr The total utility cost = 850,000/yr Compute the annualized cost. 

Ample cooling water is available at a supply temperature of 90°F and must be returned no higher than 110°F. Cooling water cost is 0.50/1,000 gal. Saturated steam is available at 150 and 600 psig. The cost of steam is 5.00/MMBtu. Electricity is available at a cost of 0.05/kWh. Use the market price for the cost of raw materials. 

F. A water condenser can easily cool to 100°F [O Brien and Schultz. 20041. The cooling water cost per year is... 

The total operating cost per year is given in Eq. (11-121. This value can be estimated as steam costs [(Eq. (11-1711 plus cooling water costs [Eq. (11-1511. The effects of various variables are summarized in Table 11-4. 

Cooling water costs are usually quite small compared to steam costs. The table above reflects the relative costs and their effect upon ejector efficiency. 

Cost of cooling water = cost of electricity + cost of chemicals for makeup water + cost of makeup water... 

Cooling water is priced on an energy basis /GJ. We usually assume the temperature rise to be 10°C. 5. Does the cooling water cost change if the return temperature changes Are there any limitations to the return temperature Explain. 

Figure 1-3. Energy cost ratio Cq/Cob relating to column operation under normal pressure pxB> as function of pressure at the column top py for various mixtures acc. to Billet, Lugowski, Mackowiak [1]. Curve 1 System toluene/ethylbenzene Curve 2 System benzene/toluene Curve 3 System methanol/ethanol. Assumption Concentration at the top xd= 1, at the bottom xw = 0, in feed xp = 0.5. Reflux ratio r/r i = heat steam cost Ch = 10 and 25 = /t, cooling water costs Ck = 0.05 = /t...

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