OS4-07 Study of the CO2-Heat Pump System Using the Capillary Tube : Part 2 Evaluation of Actual Operation Test

Natural refrigerants which are ecologically safe and were in use extensively in the pre-CFC era are witnessing a revival of CO2 (R744). Inherently being a low critical temperature (31.2 ?C) refrigerant, the CO2 cycle based system operates in transcritical mode offers an opportunity to obtain an optimum operating condition. Capillary tubes which are extensively used in small size vapour compression systems work very differently in a CO2 transcritical heat pump system. In this chapter it is described that installation of a capillary tube having an appropriately designed length replacing an expansion valve will result in a natural adjustment of the gas cooler pressure, so that the system balance always shifts to a favourable COP direction; this is contrary to the scepticism that exists on the capability of a capillary tube to attain the optimal pressure operation. There is an optimal length of capillary tube for a given diameter at which the heat pump runs optimally.

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OS4-06 Study of the CO2-Heat Pump System Using Capillary Tube : Part 1 Steady State Characteristics of the Capillary Tube

The Proceedings of the National Symposium on Power and Energy Systems ◽

10.1299/jsmepes.2005.10.173 ◽

2005 ◽

Vol 2005.10 (0) ◽

pp. 173-174

Author(s):

Kazuki HARAGUCHI ◽

Keisuke TAKAYAMA ◽

Yoshiharu AMANO ◽

Takumi HASHIZUME ◽

Michio SASAKI

Keyword(s):

Steady State ◽

Heat Pump ◽

Capillary Tube ◽

Pump System ◽

Heat Pump System

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Experimental investigation on a capillary tube based transcritical CO 2 heat pump system

Applied Thermal Engineering ◽

10.1016/j.applthermaleng.2016.10.033 ◽

2017 ◽

Vol 112 ◽

pp. 184-189 ◽

Cited By ~ 11

Author(s):

Yulong Song ◽

Jing Wang ◽

Feng Cao ◽

Pengcheng Shu ◽

Xiaolin Wang

Keyword(s):

Experimental Investigation ◽

Heat Pump ◽

Capillary Tube ◽

Pump System ◽

Heat Pump System

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Lanzhou City Sewage Heat Utilization Measurement Analysis

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.594-597.2095 ◽

2012 ◽

Vol 594-597 ◽

pp. 2095-2098

Author(s):

Jian Zhang ◽

Man Li Wang

Keyword(s):

Heat Pump ◽

Pump System ◽

Heat Pump System ◽

Lanzhou City ◽

Heat Utilization ◽

Measurement Analysis ◽

Actual Operation ◽

Sewage Source

According to the actual operation of the pick sewage-source heat pump system established by the equivalent of heating, refrigerating capacity sewage equation of lanzhou city sewage contain energy are calculated.

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Experimental investigations on adiabatic capillary tube in a transcritical CO2 heat pump system for simultaneous water cooling and heating

International Journal of Refrigeration ◽

10.1016/j.ijrefrig.2010.09.014 ◽

2011 ◽

Vol 34 (2) ◽

pp. 476-483 ◽

Cited By ~ 23

Author(s):

Neeraj Agrawal ◽

Souvik Bhattacharyya

Keyword(s):

Heat Pump ◽

Capillary Tube ◽

Experimental Investigations ◽

Water Cooling ◽

Pump System ◽

Heat Pump System

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EXPERIMENTAL VALIDATION OF A DYNAMIC MODEL FOR A RESIDENTIAL HEAT PUMP WITH IMMERSED CONDENSER

Revista de Engenharia Térmica ◽

10.5380/reterm.v14i1.62114 ◽

2015 ◽

Vol 14 (1) ◽

pp. 54

Author(s):

R. O. Nunes ◽

R. N. Faria ◽

R. N. N. Koury ◽

L. Machado ◽

R. Huebner

Keyword(s):

Dynamic Model ◽

Heat Pump ◽

Heat Exchangers ◽

Capillary Tube ◽

Heating Process ◽

Pump System ◽

Heat Pump System ◽

Water Storage Tank ◽

Modelling Methodology ◽

Mass Flow Rates

This work describes the validation of a dynamic model for a vapor compression residential heat pump with an immersed condenser. A detailed description of the modelling methodology for each component (compressor, capillary tube, evaporator, and immersed condenser) and the solution methodology employed in the complete heat pump system are presented. The main contribution of this work is in the dynamic modeling of the thermal processes occurring within the heat exchangers. Instabilities of the solutions for the heat exchangers are minimized by considering spatially and temporal varying errors. Another contribution of the model is the investigation of the temperature distribution inside the water storage tank, which highlights the possibility of using immersed condensers for this purpose without significant thermal stratification in the tank. Simulation results and experimental results are compared for transient operations using multivariate profiles of temperature, pressure and mass flow rates in heat exchangers during the water heating process.

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