Potential for the use of heat pumps for heat supply of metro stations

2018 ◽  
Vol 77 (4) ◽  
pp. 200-204 ◽  
Author(s):  
S. N. Naumenko ◽  
B. N. Minaev ◽  
I. A. Rebrov ◽  
G. B. Gusev

At present, specialists of foreign and domestic research organizations and industrial firms pay much attention to the use of steam compression heat pump plants (HPP) as an energy-saving technology. Modern compressor units allow receiving 3-4 kW for 1 kW of power consumed by HPP, and under certain conditions up to 5-6 kW of useful power. Today HPPs are most used in heat supply systems for residential and office buildings, especially in Scandinavia, Germany, Switzerland, USA, Japan, China. The paper discusses features of the operation of steam compressor heat pump plants as systems for improving energy efficiency with a description of the device of a heat pump plant; its main components are also listed. Review of the existing practice of introducing such systems in foreign countries is presented, including in Minsk - the Minsk metro, and in Russia - the Moscow Metro. The project, performed by specialists of JSC “VNIIZhT” and MIIT, is considered for the Moscow Metro (with reference to the heating systems of the Nagatinskaya and Pushkinskaya metro stations) for the use of dumping heat of ventilation shafts for heating and hot water supply, proposed by scientists of JSC “VNIIZhT” in 2012 within the framework of the exhibition of technical achievements. Authors presented information on the implementation of the pilot project at the station “Salar’yevo” (Moscow Metro) on the use of HPP in the heat and cooling supply system of the station for further comprehensive analysis of the effectiveness of the HPP application in the operating conditions of the metro. From the analysis of the data given in the work, it is concluded that metro systems are significant sources of low-potential heat, which can be used for the heat supply of stations and/or nearby urban sites by means of HPP. By now, there is a lot of experience (especially abroad) of the practical application of HPP in the heat supply systems of facilities. Nevertheless, for a reliable and comprehensive assessment of the feasibility and cost-effectiveness of projects using low-potential heat of metro systems as an energy-saving technology, a complex of studies is needed, including operational tests of currently implemented pilot projects.

The chapter is devoted to design and performance of adsorptive heat pumps. In the first sub-division, state-of-the-art of the adsorptive heat pumping is analyzed. It involves analysing operating principle of adsorptive heat pumps, comparing of the properties of adsorbents used, bed specifications, and operating conditions. Original construction of the adsorptive heat pump is designed by authors for independent heat supply systems or hot water supply of buildings and other structures for various purposes. The composites ‘silica gel – sodium sulphate' or ‘silica gel – sodium acetate' were used as adsorbents. Discharging was performed in a daytime, when heat pump supplied heating system with water warmed to 45 – 35°C. The regeneration mode proceeded at night from 0.00 to 8.00 a.m. Efficiency of suggested adsorptive heat pump is estimated by two methods: as ratio of adsorption heat to sum of desorption heat and external heat supplied to sorbent during its heating up to regeneration temperature (coefficient of performance of cycle) and as ratio of heat of adsorption to heat supplied by solar collector (net coefficient of performance). Suggested heat pump coefficients of energy performance of cycle are stated to be 2.084 when composite ‘silica gel – sodium sulphate' used and 2.021 when ‘silica gel – sodium acetate' used. Seasonal dependence of net coefficient energy performance for suggested adsorptive heat pump based on composites ‘silica gel – sodium sulphate' and ‘silica gel – sodium acetate' is revealed. Correlation of coefficients of energy performance of adsorptive heat pump and composite sorbents properties (sorption capacity and regeneration temperature) is stated. Insignificant decreasing of coefficients of energy performance when ‘silica gel – sodium acetate' used is explained by lower sorptive capacity as compared to ‘silica gel – sodium sulphate'. Suggested heat pump application perspectives are shown for heat supply systems to result from traditional energy sources independence and environmental advantages. Adsorptive heat pumps development challenges, major limitations for commercialization of adsorptive heat pumping, and requirements to ongoing innovations are analysed. The present chapter can be useful for energy efficient decentralized heat supply systems based on adsorptive heat pump unit.


Author(s):  
Mihail Sit ◽  
◽  
Anatoliy Juravliov ◽  

The work is devoted to centralized heat supply systems based on CHP plants and the use with them heat pumps (HP) on carbon dioxide as refrigerant. Heat pumps are used in heat supply systems for buildings and use the heat of the outside air and, at the same time, the heat of the return network water (WWR) as a source of low-grade heat (LHP). The aim of the study is to develop a structural diagram of such a heat pump, where the outside air is heated by a heat exchanger installed in the return water line of the heating system, to develop a hydraulic circuit of a heat pump taking into account the law of regulation of the building heating system, to develop an algorithm for controlling the operating modes of the so-called balancing heat exchanger installed after gas cooler and internal heat exchanger of the heat pump. The most significant results were the hydraulic circuit of the heat pump, the aerodynamic circuit of the air supply path to the heat pump evaporator, the balancing heat exchanger control system, taking into account the requirement to ensure the operation of the control valve in a single-phase flow. The significance of the results obtained consisted in obtaining the dependences between the CO temperature graph and the parameters of the thermodynamic cycle of the heat pump, which ensured the operation of the control valve of the heat pump in a single-phase environment.


Vestnik MEI ◽  
2018 ◽  
Vol 2 (2) ◽  
pp. 42-52
Author(s):  
Aleksandr Ya. Shelginsky ◽  
◽  
Igor V. Yakovlev ◽  

Author(s):  
Mykola Bosiy ◽  
◽  
Olexandr Kuzyk ◽  

The aim of the article is to analyze the literature and scientific publications on the effectiveness of the heat pump in heat supply systems and to study the efficiency of using the steam compression cycle of a heat pump in a heat supply system. Тo conduct energy and exergy analysis of heat pump efficiency indicators, the working fluid of which is freon R134a, when using natural waters as a source of low-potential thermal energy. The article analyzes the literature sources and scientific publications on the effectiveness of the heat pump in heat supply systems. The results of research of efficiency of application of the heat pump in systems of heat supply at use of natural waters as a source of low-potential thermal energy are presented. Energy and exergy analysis of heat pump efficiency indicators, the working fluid of which is R134a freon, was performed. The energy efficiency of the heat pump cycle was determined by the conversion factor of the heat pump. The thermodynamic efficiency of the heat pump in heat supply systems was evaluated using exergetic efficiency, which is one of the main indicators of the efficiency of heat pump processes and cycles. The calculation of energy indicators of the heat pump, such as: specific heat load in the evaporator and condenser, as well as the conversion factor of the heat pump. The calculation of exergetic efficiency for ambient temperature from +10 to -10 ºC. Thus, the energy and exergy analysis of the efficiency of the heat pump, the working fluid of which is Freon R134a with a conversion factor = 4.8. This indicates that the heat pump is a reliable, highly efficient, environmentally friendly source of energy for use in heating systems. A heat pump heating system will always consume less primary energy than traditional heating systems if natural water is used as a low-temperature heat source for the heat pump. The efficiency of the steam compression cycle of the heat pump largely depends on the temperature of low-potential heat sources. The use of HV in heating systems reduces greenhouse gas emissions compared to conventional types of heat supply, which is relevant to the ecological state of the environment.


Author(s):  
Марина Николаевна Ильина ◽  
Дмитрий Васильевич Ларюшкин

Источником информации о техническом состоянии трубопроводов тепловых сетей объектов магистральных нефтепроводов ПАО «Транснефть» являются результаты их обслуживания и ремонта, технического освидетельствования, гидравлических испытаний и т. д. На основании этих данных проводятся расчеты показателей надежности, по итогам анализа которых осуществляется планирование дальнейшего технического обслуживания и ремонта. Однако при оценке надежности систем теплоснабжения необходимо учитывать не только срок эксплуатации и величину амортизационного износа, но и реальное состояние в конкретных условиях функционирования. Учесть многообразие факторов, которые влияют на работоспособность трубопроводов системы теплоснабжения, и тем самым повысить точность расчетов при оценке их остаточного ресурса позволяет применение кластерного анализа в дополнение к используемой методике оценки надежности тепловых сетей. В рамках настоящей работы оценка надежности объектов АО «Связьтранснефть» с применением кластерного анализа проведена на примере равнозначных участков тепловых сетей двух узлов связи, расположенных в Краснодарском крае и Республике Саха (Якутия). Currently, information about technical condition of pipelines of heat supply systems at the facilities of the main oil pipelines of PJSC Transneft is formed based on the results of maintenance and repair, technical inspection, hydraulic tests, etc. Upon these data, calculations of reliability indicators of heat networks are carried out, based on the analysis of calculations further maintenance and repairs are planned. However, when assessing the reliability of heat supply systems, it is necessary to take into account not only the service life and the amount of depreciation wear of heat network elements, but also their real state in specific operating conditions. The use of cluster analysis in addition to the currently used method of heat network reliability assessment allows us to take into account the variety of factors that affect the operability of pipelines of the heat supply system, and thereby increase the accuracy of calculations when assessing their residual resource. Within the framework of this work, the reliability assessment of Svyaztransneft JSC facilities using cluster analysis was carried out on the example of equivalent sections of heat networks of two communication nodes located in the Krasnodar Territory and the Republic of Sakha (Yakutia).


2018 ◽  
Vol 39 ◽  
pp. 03007 ◽  
Author(s):  
Zoya I. Shalaginiva ◽  
Vyacheslav V. Tokarev

The paper unveils relevance of applying the methodology of multi-level modeling of thermal-hydraulic conditions of heat supply systems (HSS) and the software which are realized in the informationcomputing system “ANGARA-TS”, which make possible development of operating conditions and adjustment measures in HSS of any structure and complexity including non-standard circuit designs. Application of the multi-level modeling of HSS that is based on integration of mathematical models, methods and information technologies allows one to link the main principle of mathematical modeling that contributes to rational correspondence of the degree of mathematical model detail with the goals of its use, and modeling for different purposes. Information-computing system is implemented in a variety of real HSS of large cities in the organization of regimes and development of adjustment activities. The paper describes the experience of using new methods for development of operating conditions of large HSS in real towns.


Energies ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 4313 ◽  
Author(s):  
Boahen ◽  
Choi

The use of cascade heat pumps for hot water generation has gained much attention in recent times. The big question that has attracted much research interest is how to enhance the performance and energy saving potential of these cascade heat pumps. This study therefore proposed a new cycle to enhance performance of the cascade heat pump by adopting an auxiliary heat exchanger (AHX) in desuperheater, heater and parallel positions at the low stage (LS) side. The new cascade cycle with AHX in desuperheater position was found to have better performance than that with AHX at heater and parallel positions. Compared to the conventional cycle, heating capacity and coefficient of performance (COP) of the new cascade cycle with AHX in desuperheater position increased up to 7.4% and 14.9% respectively.


Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 479
Author(s):  
Ignacio Paniagua ◽  
Ángel Álvaro ◽  
Javier Martín ◽  
Celina Fernández ◽  
Rafael Carlier

Although CO 2 as refrigerant is well known for having the lowest global warming potential (GWP), and commercial domestic heat pump water heater systems exist, its long expected wide spread use has not fully unfolded. Indeed, CO 2 poses some technological difficulties with respect to conventional refrigerants, but currently, these difficulties have been largely overcome. Numerous studies show that CO 2 heat pump water heaters can improve the coefficient of performance (COP) of conventional ones in the given conditions. In this study, the performances of transcritical CO 2 and R410A heat pump water heaters were compared for an integrated nearly zero-energy building (NZEB) application. The thermodynamic cycle of two commercial systems were modelled integrating experimental data, and these models were then used to analyse both heat pumps receiving and producing hot water at equal temperatures, operating at the same ambient temperature. Within the range of operation of the system, it is unclear which would achieve the better COP, as it depends critically on the conditions of operation, which in turn depend on the ambient conditions and especially on the actual use of the water. Technology changes on each side of the line of equal performance conditions of operation (EPOC), a useful design tool developed in the study. The transcritical CO 2 is more sensitive to operating conditions, and thus offers greater flexibility to the designer, as it allows improving performance by optimising the global system design.


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