Sources of low potential heat. Scheme, description

Free technical library

ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING
Free library / Schemes of radio-electronic and electrical devices

Sources of low potential heat. Encyclopedia of radio electronics and electrical engineering

Free technical library

Encyclopedia of radio electronics and electrical engineering / Alternative energy sources

Comments on the article

Secondary energy resources (SER) are heat waste from technological production of industrial enterprises, municipal, household, residential and other facilities. Self-flowing geothermal waters can also be attributed to the category of WER; hot mineral springs, the warmth of which is not used in balneology; flared associated gas during oil production; produced hot oil, etc.

The issues of fuel economy through the use of VER in recent years have become an urgent problem, and are a national task. Industrial consumers currently use over 60% of all produced fuel and about 70% of all electricity generated. The efficiency of energy use in technological processes is still low and amounts to only 35-40%. In the period up to 1991, the situation with the utilization of VER in industry improved, however, the actual fuel saving achieved due to the heat of VER in relation to the possible one is 30-32%, including in the oil refining and petrochemical industry - 40%, in ferrous metallurgy - 40% , in chemical - 25%.

One of the effective ways of utilizing the heat of the VER was the production of cold for enterprises whose technological processes required it at various cooling temperatures. It should be noted that most of the enterprises of the chemical, petrochemical and other industries are cold-intensive industries and at the same time are characterized by the presence of a fairly large amount of unused SER in the form of steam, hot water, flare discharges, hot gases, etc.

But when deciding on the rational and efficient use of VER, one should not forget that along with obtaining cold, processes of heat transformation from a low-temperature level to a higher one and vice versa can also be carried out.

A public source of low-potential heat is atmospheric air, which is widely used for small heat pump installations - HPI (apartment, house). However, low air temperatures, its low heat capacity and heat transfer coefficient do not allow achieving acceptable energy efficiency indicators for large installations, in particular HP stations, to whose evaporators it is necessary to supply large heat flows.

Large non-freezing reservoirs are valuable as sources of heat for HPP. These include, for example, the Black Sea, the Caspian Sea in the middle and southern parts, Lake Issyk-Kul. On the Black Sea coast of the Caucasus and the Crimea, HPPs operate on sea water, the temperature of which in winter in these areas does not fall below 8°C. Particularly effective is the year-round use of the heat of sea water (with a temperature of 20-25 ° C in summer) for HPI hot water supply, which is a significant load in southern cities and resorts. In the transitional and winter periods of the year, cold water from reservoirs, outdoor air with a temperature above 0°C, as well as rocks (soil) can be used in HPI.

The source of low-potential heat can be low-mineralized geothermal waters, solar energy stored with the help of solar installations and heat accumulators.

However, the main sources of heat for large HPI should be considered artificial sources - heat waste. The rapid growth of energy consumption entails both the depletion of natural resources and thermal pollution of the biosphere. For example, thermal power plants, including nuclear power plants, discharge 50-55% of fuel energy with cooling water. Sometimes the decisive factor in choosing a site for the construction of a thermal power plant (NPP) is the presence of natural reservoirs that can absorb waste heat without much damage. Industrial enterprises consume huge amounts of water to cool machines and working fluids in various technological processes. The volume of water recycled and reused in industry in 1966 in our country was km3/year, and in 1980 it was 132 km3/year, or 61% of the water used by the entire industry. These "thermal rivers" have a year-round temperature of 20-40°C, which practically does not allow the use of heat directly, and are cooled in cooling towers or other evaporative coolers, giving part of the water to the atmosphere along with heat.

When replacing cooling towers with HPI evaporators, the degree of water cooling (temperature difference) while maintaining its flow rate should remain on average about 10°C.

The concentration of heat flows in circulating water supply systems can be estimated using the example of one of the largest automobile plants. The total volume of recycled water is about 75 thousand m3/h, organized in water blocks of (10-12) thousand m3/h. Water is supplied for cooling with a temperature of 30-40°C all year round and is cooled down to 15-20°C. In general, the plant releases 1300 MW of heat into the atmosphere.

Oil refineries and chemical plants are also powerful sources of secondary energy resources (SER). By type, VERs are divided into three main groups:

hot (fuel) exhaust gases of furnaces; waste unsuitable for further technological processing;
thermal WER - physical heat of waste gases of technological units; physical heat of the main, by-product, intermediate products and waste of the main production; heat of hot water and steam used in technological power plants;
VER overpressure, the potential energy of gases and liquids, which must be reduced before the next stage of the use of liquids (gases) or their release into the atmosphere.

VER heat sources can be used in ammonia heat converters (ATCs) and in heat pump installations. In heat pump installations, low-temperature heat (20-60°C) can be used, for AHT - low- and medium-potential at the level of 80-160°C, as well as high-potential heat (160-400°C). A particularly urgent task is the utilization of the heat contained in process water.

If we roughly assume that in the total (in the country) volume of circulating water supply, only 75% of water is subjected to cooling, i.e. approximately 120 km3 per year (according to the level of 1985), and the temperature difference is 10°C, then the organized discharge of low-grade heat by industry is more than 5 billion GJ per year. Water once consumed by industrial enterprises (about 40% of the total volume) is eventually canalized into natural reservoirs.

With modern requirements for environmental protection, both industrial and domestic wastewater, before being discharged into water bodies, must undergo a complex treatment system at water treatment plants or at aeration stations (in large cities). In Moscow, for example, several aeration stations discharge more than 5 million m3 / day into the Moscow River. purified water with a temperature of 16-22 °; along with water, a heat flux of 3-4 million kW also enters. Aeration stations operate in St. Petersburg, Samara and other cities. Many millions of cubic meters of water are discharged into rivers, bays, reservoirs, together with heat that can be used in HPP and convert low-grade heat into heat of a higher temperature, which can satisfy a certain part of the needs and reduce fuel consumption.

See other articles Section Alternative energy sources.

Read and write useful comments on this article.

<< Back

Latest news of science and technology, new electronics:

Energy from space for Starship 08.05.2024

Producing solar energy in space is becoming more feasible with the advent of new technologies and the development of space programs. The head of the startup Virtus Solis shared his vision of using SpaceX's Starship to create orbital power plants capable of powering the Earth. Startup Virtus Solis has unveiled an ambitious project to create orbital power plants using SpaceX's Starship. This idea could significantly change the field of solar energy production, making it more accessible and cheaper. The core of the startup's plan is to reduce the cost of launching satellites into space using Starship. This technological breakthrough is expected to make solar energy production in space more competitive with traditional energy sources. Virtual Solis plans to build large photovoltaic panels in orbit, using Starship to deliver the necessary equipment. However, one of the key challenges ... >>

New method for creating powerful batteries 08.05.2024

With the development of technology and the expanding use of electronics, the issue of creating efficient and safe energy sources is becoming increasingly urgent. Researchers at the University of Queensland have unveiled a new approach to creating high-power zinc-based batteries that could change the landscape of the energy industry. One of the main problems with traditional water-based rechargeable batteries was their low voltage, which limited their use in modern devices. But thanks to a new method developed by scientists, this drawback has been successfully overcome. As part of their research, scientists turned to a special organic compound - catechol. It turned out to be an important component that can improve battery stability and increase its efficiency. This approach has led to a significant increase in the voltage of zinc-ion batteries, making them more competitive. According to scientists, such batteries have several advantages. They have b ... >>

Alcohol content of warm beer 07.05.2024

Beer, as one of the most common alcoholic drinks, has its own unique taste, which can change depending on the temperature of consumption. A new study by an international team of scientists has found that beer temperature has a significant impact on the perception of alcoholic taste. The study, led by materials scientist Lei Jiang, found that at different temperatures, ethanol and water molecules form different types of clusters, which affects the perception of alcoholic taste. At low temperatures, more pyramid-like clusters form, which reduces the pungency of the "ethanol" taste and makes the drink taste less alcoholic. On the contrary, as the temperature increases, the clusters become more chain-like, resulting in a more pronounced alcoholic taste. This explains why the taste of some alcoholic drinks, such as baijiu, can change depending on temperature. The data obtained opens up new prospects for beverage manufacturers, ... >>

Random news from the Archive

The capacity of hard drives will dramatically increase 01.04.2012

Seagate was able to increase the data density in the hard drive by 55% - up to 1 Tbps per square inch. It is expected that the new technology within the next 10 years will make it possible to create hard drives with a capacity of up to 60 TB. Seagate Technology, the world's largest magnetic storage maker, has announced that it has achieved a data density of 1 Tbit (1 trillion bits) per square inch of hard drive platter. Seagate claims to be the first in the market to reach this milestone and reports that the 1 trillion bits that the company's new technology can record per 1 square inch is significantly more than the stars in our galaxy, the number of which ranges from 200 to 400 billion .

It was possible to increase the density of data recording due to the transition to a new generation technology called thermally assisted magnetic recording (HAMR), Seagate said. This technology opens up new perspectives in the traditional hard drive market. The company claims that on its basis over the next 10 years it will be possible to create hard drives with a capacity of up to 60 TB. The current-generation technology used in today's hard drives, called Perpendicular Magnetic Recording (PMR), will reach the 1TB per square inch limit within the next few years, after which it will no longer be developed, Seagate stressed.

PMR technology, in turn, has replaced the longitudinal recording technology that has been used since the inception of the personal magnetic storage market in 1956. Today, PRM offers a recording density of 620 Gbps per square inch. Thus, already now HAMR technology offers a 55% increase in density. The company said that the new technology solves the problem of data distortion, which occurs in current generation technology due to the fact that the cell size becomes too small.

The capacity of modern hard drives with a recording density of 620 Gb per square inch is 3 TB in the case of a 3,5-inch form factor and 750 GB in the case of a 2,5-inch one. HAMR technology already at the initial stage will make it possible to create hard drives with a capacity of 6 and 2 TB, respectively. The maximum theoretical density when using HAMR is 5-20 Tbps per square inch. This is equivalent to a 3,5-30TB 60" HDD and a 2,5-10TB 20" HDD.

"The development of social networks, search technologies, cloud computing, the growth of multimedia content and other areas force us to look for new ways to increase capacity," commented Mark Re, Seagate's senior vice president of engineering. "Innovations such as HAMR, will play a key role in the further development of the information industry."

Note that the magnetic storage market is going through hard times. It was hit by floods in Thailand last year, which led to a shortage of hard drives and reduced shipments of personal computers to the global market. In addition, manufacturers are under increasing competitive pressure from flash memory. In August 2011, major vendors formed an alliance to shape the future of the hard drive industry.

Other interesting news:

▪ Miniature Precision ADCs MAX11259 and MAX11261

▪ Improving the Reliability of Powerful Silicon Carbide Semiconductors

▪ Synthetic wood is not afraid of fire

▪ Memory programmer BK PRECISION 848

▪ Ointment for snake bites

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ site section Electric meters. Article selection

▪ article Hallway wall. Tips for the home master

▪ article What superpowers does a comic book hero called normalman have? Detailed answer

▪ fuchsia article. Legends, cultivation, methods of application

▪ article Refinement of TRX RA3AO. Encyclopedia of radio electronics and electrical engineering

▪ article Scheme for regulating the speed of rotation of a DC motor on the map. Encyclopedia of radio electronics and electrical engineering

Leave your comment on this article:

All languages of this page

Home page | Library | Articles | Website map | Site Reviews