Gas heat pump technology and its application

Abstract: This paper introduces the working principle and application of the gas heat pump, which shows that the gas heat pump can ease the power shortage and adjust the seasonal unevenness of the gas consumption, which is beneficial to save energy and protect the environment.

Author: Jiao Wenling (Harbin University of Architecture Department of Thermal Engineering, Harbin 150008)

XU Jie (Harbin Gas and Chemical Group Corporation, Harbin 150008)

CLC number TU996.79 TK511.2

1 Introduction

From the latest energy forecast, we can see that the energy consumption in 2030 is almost double that of the current level (see Table 1), and the consumption of natural gas, which accounts for more than 20% of energy, is also increasing simultaneously (Table 2). In developing countries like ours, energy consumption is projected to increase dramatically due to population growth and the establishment of a large number of energy-consuming industrial production installations.

Table 1 Global Energy Consumption Forecast

Era consumption EJ
1992 326
2010 450
2030 610

Table 2 Global Natural Gas Consumption Forecast

Era consumption EJ
1992 75
2000 96
2010 114
2030 130

This has led to environmental problems. In order to prevent and reduce air pollution, many countries have strict limits on the emission of combustion equipment (see Table 3). The emission limit of gaseous fuels is stricter than that of coal or petroleum, The advantages of fuel.

Table 3 Large combustion equipment emission limits

Emission limit (mg / m3)
Combustion SO2 NOX dust solid 400 ~ 2 000 650 50 ~ 100
Liquid 400 ~ 1 700 450 50
Gaseous 35 350 5

This paper attempts to introduce the principle and application of gas heat pump to promote the development of gas heat pump in our country, to save energy and protect the environment.

2 gas heat pump works

2.1 heat pump working principle

Heat pump one

Figure 1 heat pump operating temperature range

The working principle of the heat pump with the same refrigerator, are reverse cycle heat engine work. According to the second law of thermodynamics, when high energy consumption W is used as a compensation condition, Q1 heat can be extracted from the low-temperature heat source and transferred to the high-temperature heat source Q2, as shown in FIG. 1. Heat pumps draw heat from ambient temperatures and heat them to high-temperature heat sources or radiate heat to a relatively high-temperature heat source, creating a cool environment at a low temperature (cooling) or cooling and heating at the same time.

One of the most simple vapor compression heat pump is composed of compressor, condenser, throttle, evaporator composition, the working principle shown in Figure 2.

Heat pump two

Figure 2 Vapor compression heat pump working principle

In principle, all kinds of engines can be used, such as motors, fuel engines, and external combustion engines. However, the energy they can consume is not the same value. When evaluating the value of energy, it depends not only on its quantity, Also depends on its quality, energy according to their quality can be divided into high and low energy can be two.

In theory, we can evaluate the performance of a heat pump system using the coefficient of heating performance εh:

Heat pump three

However, considering the quality of energy, it is more reasonable to evaluate the energy saving effect of the heat pump by using the energy utilization factor. Energy efficiency factor E is defined as the ratio of primary energy used to heat and consumed.

Heat pump low temperature heat source can be air, well water, sea water, soil heat, solar energy, etc., the advantage of heat pump is that it effectively uses the energy of these low-temperature heat source, consume a certain amount of high energy, the heat is High energy consumption and low calorie absorption, thus saving high energy, especially for some industrial sectors (such as meat processing plants), the process needs both cooling and heating of the occasion, the use of heat pump device It seems more economical and reasonable.

2.2 gas heat pump

The gas engine driven gas heat pump, with all the advantages of the heat pump itself, but also both gas combustion emissions less features; the other gas engines and high efficiency, generally more than 30% (higher than the total efficiency of power generation 27%), if you take full advantage of this gas engine exhaust, cylinder cooling jacket waste heat, you can get a higher energy efficiency. For example: energy-driven heat pump energy utilization factor E = η1η2εh, thermal power efficiency η1 = 0.3, transmission and distribution efficiency η2 = 0.9, εh take 3, then E = 0.81. The gas-driven heat pump, heat engine efficiency η = 0.37, εh = 3, then E = 0.37 × 3 = 1.11, then consider the use of water jacket waste heat 46%, then E = 1.11 +0.46 = 1.57.

In recent years, the rapid development of gas absorption heat pump, heat pump is another form of drive, which consumes heat to heat the absorbent to complete this heat transfer from the low-temperature heat source to high-temperature heat source of spontaneous process.

3 gas heat pump applications

In industrialized countries, about 80% of the energy consumed by buildings, including residential and commercial buildings, accounts for about 26.6% of total consumption for heating, air conditioning and hot water supply. When there is a suitable low-level heat source, it is a fact that many countries in the world have become a reality to replace gas-fired boiler room heating and electrical air-conditioners with gas heat pumps in order to protect the environment and ease power shortage.

At present, the most used in the building is the air-source heat pump. This heat pump room air conditioner has a whole and separate. Split-type heat pump room air conditioner sub-indoor and outdoor two parts, through the switching valve in the winter to achieve heating cycle, in the summer to achieve the refrigeration cycle. This type of air conditioner is easy to install, high degree of automation, easy to operate.

Abroad as early as the seventies has successfully developed a similar gas-powered air ─ ─ air heat pump unit, it can be for residential cooling, heating, hot water supply.

China has put into operation gas direct-fired absorption chiller, also both cooling and heating, it uses concentrated lithium bromide solution as absorbent to absorb the refrigerant ─ ─ water, is a non-fluoride equipment, known as the green air-conditioning. The unit vibration, low noise, simple operation, easy maintenance.

At present, foreign gas heat pump has a wide range of markets. Residential natural gas engine brake heat pump has been commercialized in the United States. It has advantages in terms of efficiency, reliability and comfort, and it has been proven that the critical life of the structure can reach 15 years. Breakthroughs have also been made in the study of controlling air humidity in the UK. The developed gas desander wheel is divided into two sections. One section absorbs damp air while the other section heats the gas heated dry air to heat the desiccant. This continuous operation significantly reduces the operating costs associated with conventional moisture reduction.

4 Conclusion

(1) A heat pump is a device that can be dragged by a high position to force heat to flow from a low heat source to a high heat source. It uses the high energy sources reasonably and utilizes an inexhaustible low energy source, apparently Save energy

(2) The use of gas heat pump can ease the situation of urban power shortage. China's power is still quite tense, rational use of energy, reduce the burden on electricity This will be our long-term policy.

(3) The gas supply in our country, especially the natural gas supply, has made great progress. It provides the prerequisite for the development and utilization of the gas heat pump. Meanwhile, the use of the gas heat pump is beneficial to the solution of the contradiction between supply and demand of gas.

(4) At the beginning of the next century, China's energy demand will rapidly increase. China should energetically devote itself to the research and development of gas-fired heat pumps. The state should also formulate some favorable policies to promote the use of gas-fired heat pumps, so as to save energy, Technology for environmental protection can play an equally important role in our country.

TECHNOLOGY AND APPLICATION FOR GAS HEAT PUMP

Jiao Wenling Xu Jie
(Dept. of Thermocal Energy, Haerbin Architect University, Haerbin 150008, China)

ABSTACT This article introduces the work principle and application for gas heat pump, recounts that developing of gas heutpumpcould mitigrate electricity intense conditions, regulates seasonal gas, but also benefits for saving energy sources, protects surroundings.
KEY WORDS gas heat pump, principle, application

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