Daily Archives March 12, 2016

Geothermal Direct Use

JOHN W. LUND

Geo-Heat Center, Oregon Institute of Technology Klamath Falls, Oregon, United States

1. Utilization

2. Equipment

3. Economic Considerations

4. Future Developments

Glossary

agribusiness application Agriculture and aquaculture de­velopments; in this article, it includes the heating of the various applications, such as greenhouses and fish ponds. aquaculture pond/raceway heating Heat energy provided to ponds and raceway in order to optimize the growing of fish, shrimp, alligators, or other aquatic species. balneology The use of mineral waters for therapeutic purposes.

direct use The use of the heat energy rather than its conversion to other forms such as electricity; for example, a furnace used for space heating...

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THE ROLE OF HEAT STORAGE

The different components of the climate system contribute on different timescales to climate varia­tions and change. The atmosphere and oceans are fluid systems and can move heat through convection and advection in which the heat is carried by the currents, whether small-scale short-lived eddies or large-scale atmospheric jet streams or ocean currents. Changes in phase of water, from ice to liquid to water vapor, affect the storage of heat. However, even ignoring these complexities, many facets of the climate are determined simply by the heat capacity of the different components of the climate system. The total heat capacity considers the mass involved as well as its capacity for holding heat, as measured by the specific heat of each substance.

The atmosphere does not have much capability...

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CONSUMER COUNTRY STRATEGIES

OPEC’s ability to raise prices in the short run to levels that may be damaging to the economies of major consuming countries poses a major policy challenge to the governments of consuming coun­tries. Rising oil prices threaten consumer country national interest in several ways. Oil price volatility can inhibit investment, inhibit economic growth, and spur inflation in major economies that purchase consumer country exports.

The burden of rising energy import costs also threatens social stability in key regional consuming countries such as India and Pakistan and the South­east Asia region. Moreover, supply constraints also make it easier for governments or subnational groups to threaten vital interests of the United States, Japan, and their allies.

Thus, consuming countries have a clear ...

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ICE

Major ice sheets, such as those over Antarctica and Greenland, have a large heat capacity but, like land, the penetration of heat occurs primarily through conduction so that the mass involved in changes from year to year is small. Temperature profiles can be taken directly from bore holes into ice and it is estimated that terrestrial heat flow is 51 mW/m2. On century timescales, however, the ice sheet heat capacity becomes important. Unlike land, the ice can melt, which has major consequences through changes in sea level on longer timescales.

Sea ice is an active component of the climate system that is important because it has a high albedo. A warming that reduces sea ice, reduces the albedo and hence enhances the absorption of solar radiation, amplifying the original warming...

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THE LAND

The heat penetration into land is limited and slow, as it occurs mainly through conduction, except where water plays a role. Temperature profiles taken from bore holes into land or ice caps provide a coarse estimate of temperatures in years long past. Conse­quently, surface air temperature changes over land occur much faster and are much larger than those over the oceans for the same heating, and because we live on land, this directly affects human activities. The land surface encompasses an enormous variety of topographical features and soils, differing slopes (which influence runoff and radiation received), and water capacity. The highly heterogeneous vegetative cover is a mixture of natural and managed ecosys­tems that vary on very small spatial scales...

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CONSUMER COUNTRY POWER IN A DEREGULATED SETTING

As discussed previously, the United States is a major buyer of imported crude oil, and its imports represent a large share of the market for internation­ally ‘‘traded’’ oil. Given the large scale of U. S. purchases, incremental U. S. acquisitions of oil affect the overall international market price of oil. Stated another way, the cost of each marginal barrel is higher than the price paid for that barrel given that this additional purchase affects the costs of all oil consumed. From the perspective of the United States, this constitutes an externality in the sense that consumers will base their decisions regarding the quantity of oil (and oil products) purchased on the average, rather than the marginal, cost of oil...

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THE OCEANS

The oceans cover 70.8% of the surface of the earth, although there is a much greater fraction in the Southern Hemisphere (80.9% of the area) than the Northern Hemisphere (60.7%), and through their fluid motions and high heat capacity they have a central role in shaping the earth’s climate and its variability. The average depth of the ocean is 3795 m. The oceans are stratified opposite to the atmosphere, with warmest waters near the surface. Consequently, in the ocean, convection arises from cooling at the surface and transport of heat upwards occurs through colder and denser waters sinking and being replaced by lighter and more buoyant waters. Another vital factor in convection is the salinity of the water because this also affects density...

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THE HYDROLOGICAL CYCLE

Driven by exchanges of energy, the hydrological cycle involves the transfer of water from the oceans to the atmosphere, to the land, and back to the oceans both on top of and beneath the land surface. In the tropics in summer, land warms relative to the ocean and sets the stage for monsoon development. Water is evaporated from the ocean surface, cooling the ocean. As water vapor, it is transported perhaps thousands of kilometers before it is involved in clouds and weather systems and precipitated out as rain, snow, hail, or some other frozen pellet back to the earth’s surface. During this process, it heats the atmosphere. Over land, soil moisture and surface waters can act through evaporative cooling to moderate tempera­tures...

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