Lake-source cooling

The DLWC concept has sparked interest elsewhere. Cornell University has proposed a 55-million project called Lake Source Cooling [8] would reduce Cornell s air-conditioning energy usage by 80% by tapping nearby Cayuga Lake. 

Schematic diagram for proposed lake source cooling system.

The lake-source cooling proposed by Cornell University in the Cornell Chronicle (June 30, 1994) is claimed to have economic benefits as well as environmental virtues. (See Exercise 3.31 for a description of the scheme.) Cornell has two options. 

Option 1. Replace present refrigerators with similar refrigerators at a cost of 20 x 10. Option 2. Replace present refrigerators with lake-source cooling at a cost of 50 x 10. ... 

However, the lake-source cooling would save 1.5 x 10 /year in electricity costs. 

Assume a 10-year straight-line depreciation for both options. Do you agree with the utilities engineers conclusion that lake-source cooling is economically advantageous ... 

Drought Excluded by assuming that there are multipie sources of the ultimate heat sink or that the ultimate heat sink is not affected by drought (e.g., cooling tower with adequately sized basin) Low lake Internal or river water Ultimate heat. sink is designed for at ii.-av. 30 days of operation... 

Closed-cycle cooling water systems employing cooling towers give higher temperatures than direct open-cycle cooling from river, lakes or other large water sources. 

Obsidian, a volcanic glass, is generally formed when volcanic lava comes in contact with water. Often the lava pours into a lake or an ocean and is cooled quickly. This process produces a glassy texture. Many studies are devoted to the determination of source sites as it is a very widespread material in prehistory used for tools [36]. Coote et at. [37] examined 120 specimens by means of proton-induced y-ray emission (PIGE) and found that the F/Na ratio is well suited to distinguish between different source sites. Melanesian obsidian was studied using the same method [38,67]. 

The behavior of gases dissolving in water appears to be less complex. The solubility of a gas in water typically decreases with increasing temperature, as shown for several cases in Fig. 17.6. This temperature effect has important environmental implications because of the widespread use of water from lakes and rivers for industrial cooling. After being used as a coolant, the water is returned to its natural source at a higher-than-ambient temperature (thermal pollution has occurred). Because it is warmer, this water contains less than the normal concentration of oxygen and is also less dense it... 

Thermal pollution the oxygen-depleting effect on lakes and rivers of using water for industrial cooling and returning it to its natural source at a higher temperature. (17.3)... 

Cooling towers are used in many industrial areas to cool water to remove excess heat produced by fuel combustion or by other reactions. Nowhere is more cooling water used than in the production of electricity from nuclear fission. In virtually every cooling tower application, cool water is taken from a surface source (river, estuary, or lake) and is returned to its source heated up. The introduction of warmed water to its source disrupts marine plant and animal life and also catalyzes chemical reactions. These have the effect of increasing the concentrations of toxic chemicals in water, which is often taken up for drinking use downstream... 

Consider the sources of some of the common chemical raw materials and relate these to products that are accessible via one or two chemical transformations in a typical chemical complex. Starting with just a few simple components—air, water, salt (NaCl), and ethane—together with an external source of energy, quite a range of finished products is possible (Fig. 1.1). While it is unlikely that all of these will be produced at any one location, many will be, and all are based on commercially feasible processes [1]. Thus, a company which focuses on the electrolytic production of chlorine and sodium hydroxide from salt will often be sited on or near natural salt beds in order to provide a secure source of this raw material. A large source of freshwater, such as a river or a lake will generally be used for feedstock and cooling water... 

Environmental problems can also be present when renewable sources of energy are used. Condensed steam from geothermal plants may have to be cleaned up before it can be discharged. Reinjection into the reservoir avoids this problems. Hydropower requires dams that remove the niches in running streams that foster biodiversity. Cool, well-aerated running water favors different species more than lakes do. A shaded stream can have a different flora and fauna that may be more diverse than that in the sunny lake behind the dam. The dams also interfere with the... 

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