scholarly journals Refrigerant Charge Fault Detection and Diagnosis Algorithm for Water-to-Water Heat Pump Unit

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 545 ◽  
Author(s):  
Samuel Boahen ◽  
Kwang Lee ◽  
Jong Choi
Keyword(s):  
Fault Detection ◽  
Heat Pump ◽  
Heat Pumps ◽  
Fault Detection And Diagnosis ◽  
Pump Unit ◽  
Cooling Mode ◽  
Heat Pump Unit ◽  
Detection And Diagnosis ◽  
Heating Mode ◽  
Fault Characteristic

Refrigerant charge faults have a great adverse effect on the performance of heat pumps and must therefore be detected and diagnosed early in real time. In this study, the effect of refrigerant charge faults on a water-to-water heat pump is experimentally investigated in cooling mode and heating mode at various outdoor entering water temperature conditions. The study showed that refrigerant undercharge affects the performance of water-to-water heat pump more in heating mode than in cooling mode. Results from the study are used to develop a refrigerant charge fault detection and diagnosis (FDD) algorithm that works using correlations and rule-based refrigerant fault characteristic charts. The FDD algorithm is able to detect refrigerant charge faults in the water-to-water heat pump within an error threshold of ±4.5% and ±1.1% in cooling mode and heating mode respectively.

scholarly journals Fault Detection Methodology for Secondary Fluid Flow Rate in a Heat Pump Unit

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2974
Author(s):  
Samuel Boahen ◽  
Kwesi Mensah ◽  
Yujin Nam ◽  
Jong Min Choi
Keyword(s):  
Fluid Flow ◽  
Fault Detection ◽  
Heat Pump ◽  
Flow Rate ◽  
Heat Pumps ◽  
Fault Detection And Diagnosis ◽  
Fluid Flow Rate ◽  
Pump Unit ◽  
Heat Pump Unit ◽  
Secondary Fluid

Fault detection and diagnosis (FDD) has become an important subject in heat pumps due to its potential for energy savings. However, research on multiple faults occurring at the secondary fluid side of heat pumps is rare in the open literature. This study experimentally examined single secondary fluid flow rate faults (SSFF) and multiple-simultaneous secondary fluid flow rate faults (MSSFF) and their effects on the performance of a heat pump unit, which is a core component of ground source heat pump systems, and proposed FDD methodology to detect these faults. The secondary fluid flow rate faults were simulated in cooling mode by varying the evaporator and condenser secondary fluid flow rates at 60%, 80%, 100%, 120%, and 140% of the reference value according to varying outdoor entering water temperature conditions. Condenser secondary fluid flow rate faults affected the heat pump coefficient of performance(COP) significantly more than the evaporator secondary fluid flow rate fault in SSFF. Cooling capacity was highly dependent on the evaporator secondary fluid flow rate fault while COP was greatly affected by the condenser secondary fluid flow rate fault in MSSFF. The FDD methodology was modeled using correlations and performance trends of the heat pump and can detect SSFF and MSSFF within an error threshold of ±1.6% and ±6.4% respectively.

scholarly journals Geothermal energy: shallow sources

2014 ◽  
Vol 126 (2) ◽  
pp. 25
Author(s):  
Ian Johnston
Keyword(s):  
Heat Pump ◽  
Geothermal Energy ◽  
Heat Pumps ◽  
Cooling Mode ◽  
Ground Source Heat Pumps ◽  
Heating And Cooling ◽  
Ground Source ◽  
Heating Mode ◽  
To Receive ◽  
Ground Energy

Below a depth of around 5 to 8 metres below the surface, the ground displays a temperature which is effectively constant and a degree or two above the weighted mean annual air temperature at that particular location. In Melbourne, the ground temperature at this depth is around 18°C with temperatures at shallower depths varying according the season. Further north, these constant temperatures increase a little; while for more southern latitudes, the temperatures are a few degrees cooler. Shallow source geothermal energy (also referred to as direct geothermal energy, ground energy using ground source heat pumps and geoexchange) uses the ground and its temperatures to depths of a few tens of metres as a heat source in winter and a heat sink in summer for heating and cooling buildings. Fluid (usually water) is circulated through a ground heat exchanger (or GHE, which comprises pipes built into building foundations, or in specifically drilled boreholes or trenches), and back to the surface. In heating mode, heat contained in the circulating fluid is extracted by a ground source heat pump (GSHP) and used to heat the building. The cooled fluid is reinjected into the ground loops to heat up again to complete the cycle. In cooling mode, the system is reversed with heat taken out of the building transferred to the fluid which is injected underground to dump the extra heat to the ground. The cooled fluid then returns to the heat pump to receive more heat from the building.

scholarly journals Performance of heat pump unit with capillary heat exchanger*

2018 ◽  
Vol 175 ◽  
pp. 02031
Author(s):  
Zhenpeng Bai ◽  
Yanfeng Li
Keyword(s):  
Heat Exchanger ◽  
Heat Pump ◽  
Clean Energy ◽  
Pump Unit ◽  
Cooling Mode ◽  
Pump System ◽  
Heat Pump System ◽  
Collection Device ◽  
Heat Pump Unit ◽  
Shallow Geothermal Energy

The heat pump system utilizes shallow geothermal energy in the coastal areas, which not only uses clean energy but also contributes to energy conservation and environmental protection. This paper studies the performance of a heat pump system applied a capillary heat exchanger as an energy collection device. The numerical performance of capillary heat pump showed a good agreement with the experimental data in the winter heating mode and the summer cooling mode. It was concluded that the COP of the heat pump unit using the capillary heat exchanger was 5.32 in winter and 4.32 in summer.

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