scholarly journals Assessment of options to reduce pollutant emissions in single-family houses in north-eastern Poland

2020 ◽  
Vol 154 ◽  
pp. 07005
Author(s):  
Joanna Hałacz ◽  
Aldona Skotnicka-Siepsiak ◽  
Maciej Neugebauer ◽  
Krzysztof Nalepa ◽  
Piotr Sołowiej
Keyword(s):  
Heat Transfer ◽  
Mechanical Ventilation ◽  
Heat Exchanger ◽  
Heat Pump ◽  
High Efficiency ◽  
Real Life ◽  
Pollutant Emissions ◽  
Single Family ◽  
Biomass Boiler ◽  
Final Energy

The article presents the results of a study aiming to select the optimal source of heat for a newly designed single-family home. Commercial software was used to compare heating and ventilation systems involving a bituminous coal boiler, a condensing gas boiler, a biomass boiler, and a heat pump with water and glycol as heat transfer media. The effectiveness of natural ventilation, mechanical ventilation with a ground-coupled heat exchanger, and solar heater panels (flat and tubular) for water heating was evaluated. The analysis was based on the annual demand for useful energy, final energy and non-renewable primary energy in view of the pollution output of the evaluated heating systems. The analysis revealed that the heat pump with water and glycol as heat transfer media was the optimal solution. However, the performance of the heat pump in real-life conditions was below its maximum theoretical efficiency. The biomass boiler contributed to the highest reduction in pollutant emissions, but it was characterized by the highest demand for final energy. Mechanical ventilation with heat recovery was required in all analyzed systems to achieve the optimal results. Laboratory analyses confirmed the high efficiency of the tube heat exchanger in winter.

scholarly journals Assessment of Reducing Pollutant Emissions in Selected Heating and Ventilation Systems in Single-Family Houses

Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1224 ◽  
Author(s):  
Joanna Hałacz ◽  
Aldona Skotnicka-Siepsiak ◽  
Maciej Neugebauer
Keyword(s):  
Mechanical Ventilation ◽  
Heat Pump ◽  
Carbon Dioxide Emissions ◽  
Natural Ventilation ◽  
Pollutant Emissions ◽  
Single Family ◽  
Heating Systems ◽  
Biomass Boiler ◽  
Final Energy ◽  
Ventilation Systems

The article presents the results of a study aiming to select the optimal source of heat for a newly designed single-family home. Commercial software was used to compare heating and ventilation systems involving a bituminous coal boiler, a condensing gas boiler, a biomass boiler, a heat pump with water and glycol as heat transfer media. The effectiveness of natural ventilation, mechanical ventilation with a ground-coupled heat exchanger, and solar heater panels for water heating were evaluated. The analysis was based on the annual demand for useful energy, final energy, and non-renewable primary energy in view of the pollution output of the evaluated heating systems. The analysis revealed that the heat pump with water and glycol was the optimal solution. However, the performance of the heat pump in real-life conditions was below its maximum theoretical efficiency. The biomass boiler contributed to the highest reduction in pollutant emissions (according to Intergovernmental Panel on Climate Change Change guidelines, carbon dioxide emissions have zero value), but it was characterized by the highest demand for final energy. Mechanical ventilation with heat recovery was required in all analyzed systems to achieve optimal results. The introduction of mechanical ventilation decreased the demand for final energy by 10% to around 40% relative to the corresponding heating systems with natural ventilation.

Performance Evaluation of a Vertical U-Tube Ground Heat Exchanger Using a Numerical Simulation Approach

2013 ◽  
Vol 724-725 ◽  
pp. 909-915
Author(s):  
Ping Fang Hu ◽  
Zhong Yi Yu ◽  
Fei Lei ◽  
Na Zhu ◽  
Qi Ming Sun ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Performance Evaluation ◽  
Heat Exchanger ◽  
Heat Pump ◽  
Heat Transfer Process ◽  
Working Fluid ◽  
Outlet Temperature ◽  
Ground Heat Exchanger ◽  
Ground Source Heat Pump ◽  
Ground Source

A vertical U-tube ground heat exchanger can be utilized to exchange heat with the soil in ground source heat pump systems. The outlet temperature of the working fluid through the U-tube not only accounts for heat transfer capacity of a ground heat exchanger, but also greatly affects the operational efficiency of heat pump units, which is an important characteristic parameter of heat transfer process. It is quantified by defining a thermal effectiveness coefficient. The performance evaluation is performed with a three dimensional numerical model using a finite volume technique. A dynamic simulation was conducted to analyze the thermal effectiveness as a function of soil thermal properties, backfill material properties, separation distance between the two tube legs, borehole depth and flow velocity of the working fluid. The influence of important characteristic parameters on the heat transfer performance of vertical U-tube ground heat exchangers is investigated, which may provide the references for the design of ground source heat pump systems in practice.

scholarly journals Performance and Exergy Transfer Analysis of Heat Exchangers with Graphene Nanofluids in Seawater Source Marine Heat Pump System

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1762 ◽  
Author(s):  
Zhe Wang ◽  
Fenghui Han ◽  
Yulong Ji ◽  
Wenhua Li
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Pump ◽  
Heat Exchangers ◽  
Transfer Model ◽  
Enhanced Heat Transfer ◽  
Pump System ◽  
Heat Pump System ◽  
Tube Heat Exchanger ◽  
Exergy Transfer

A marine seawater source heat pump is based on the relatively stable temperature of seawater, and uses it as the system’s cold and heat source to provide the ship with the necessary cold and heat energy. This technology is one of the important solutions to reduce ship energy consumption. Therefore, in this paper, the heat exchanger in the CO2 heat pump system with graphene nano-fluid refrigerant is experimentally studied, and the influence of related factors on its heat transfer enhancement performance is analyzed. First, the paper describes the transformation of the heat pump system experimental bench, the preparation of six different mass concentrations (0~1 wt.%) of graphene nanofluid and its thermophysical properties. Secondly, this paper defines graphene nanofluids as beneficiary fluids, the heat exchanger gains cold fluid heat exergy increase, and the consumption of hot fluid heat is heat exergy decrease. Based on the heat transfer efficiency and exergy efficiency of the heat exchanger, an exergy transfer model was established for a seawater source of tube heat exchanger. Finally, the article carried out a test of enhanced heat transfer of heat exchangers with different concentrations of graphene nanofluid refrigerants under simulated seawater constant temperature conditions and analyzed the test results using energy and an exergy transfer model. The results show that the enhanced heat transfer effect brought by the low concentration (0~0.1 wt.%) of graphene nanofluid is greater than the effect of its viscosity on the performance and has a good exergy transfer effectiveness. When the concentration of graphene nanofluid is too high, the resistance caused by the increase in viscosity will exceed the enhanced heat transfer gain brought by the nanofluid, which results in a significant decrease in the exergy transfer effectiveness.

Simulation on Ground Temperature Change of GSHP System in Severe Cold Regions

2014 ◽  
Vol 945-949 ◽  
pp. 2820-2824 ◽  
Author(s):  
Li Bai ◽  
Peng Xuan Wang
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Temperature Change ◽  
Heat Pump ◽  
Ground Heat Exchanger ◽  
Ground Source Heat Pump ◽  
Cold Regions ◽  
Ground Source ◽  
Ground Coupled Heat Pump ◽  
Operation And Management

For the case of ground-source heat pump in severe cold regions in winter, the heat transfer situation of the ground and ground heat exchanger was dynamically simulated according to the statistics of a project in Changchun to analysis the change of the ground heat, which provided references for the initial design and operation and management of the ground-coupled heat pump in severe cold regions.

System Design of a 2.0 MWth Sodium/Molten Salt Pilot System

2020 ◽  
Author(s):  
Kenneth M. Armijo ◽  
Matthew D. Carlson ◽  
Dwight S. Dorsey ◽  
Joshua M. Christian ◽  
Craig S. Turchi
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
System Design ◽  
Molten Salt ◽  
High Efficiency ◽  
Performance Model ◽  
Transfer Coefficients ◽  
Storage Duration ◽  
Pump Speed ◽  
Receiver System

Abstract Nitrate molten salt concentrating solar power (CSP) systems are currently deployed globally and are considered state-of the art heat transfer fluids (HTFs) for present day high-temperature operation. Although slightly higher limits may be possible with molten salt, to fully realize SunShot efficiency goals of $15/kWhth HTFs and an LCOE of 6¢/kWh, HTF technologies working at higher temperatures (e.g., 650 °C to 750 °C) will require an alternative to molten salts, such as with alkali metal systems. This investigation explores the development of a 2.0 MWth sodium receiver system that employs a sodium receiver as the HTF, as well as with a ternary chloride (20%NaCl/40%MgCl/40%KCl by mol wt.%) salt as a thermal energy storage (TES) medium to facilitate a 6-hr. storage duration. A sodium-to-salt heat exchanger model as well as a salt-to-sCO2 primary heat exchanger model are employed and evaluated in this investigation. A thermodynamic system design model was developed using Engineering Equation Solver (EES) where state properties were calculated at inlets and outlets along both hot and cold legs of the pilot-scale plant. This investigation assesses receiver performance as well as system efficiency studies for the pump and system operational ranges. Results found that high efficiency sodium receivers were found to have higher heat transfer coefficients and required far less spreading of incident flux. The system performance model results suggest that for a pump speed of 2400 RPM, respective hot and cold pump TDH values were determined to be 260.1–307 ft. and 260.1–307 ft for pump flow rates of 90–120 GPM.

Experimental Study on Thermal Hydraulic Characteristics of Steam Condensation in Capillary Glass Tubes

2009 ◽  
Author(s):  
Koji Iiyama ◽  
Akiko Kaneko ◽  
Yutaka Abe ◽  
Yutaka Suzuki
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
High Efficiency ◽  
Capillary Tube ◽  
Glass Tube ◽  
Phase Changes ◽  
Vapor Flow ◽  
Hydraulic Characteristics ◽  
Microchannel Heat Exchanger ◽  
Condensation Flow

At present, a microchannel heat exchanger is requested to achieve high efficiency in small size energy equipments. In order to clarify the heat transfer mechanism in a microchannel heat exchanger, knowledge on the thermal hydraulic characteristics of condensation flow in the channels is essential. However, study on the thermal hydraulic characteristics of condensation flow in a microchannel is hardly conducted except visualization of flow patterns. Objectives of the present study are to estimate the heat transfer performance of the present device and to observe the condensation behavior of vapor flow to clarify the thermal hydraulic characteristics of condensation flow in a capillary tube. As the results, it is confirmed that the microchannel heat exchanger realizes heat exchange of 7 kW when phase changes. In a single capillary glass tube as a simulated unit microchannel, the annular flow, the injection flow and the bubbly flow in a capillary tube are observed. According to the comparison of the present device and the glass tube experiment, it is suggested that the flow structure in the microchannel heat exchanger is almost same as that in the glass capillary tube.

Application Study of Newly Developed Turbo Heat Pump for 130 Degrees Celsius Water for an Industrial Process

2011 ◽  
Author(s):  
Shuichi Umezawa ◽  
Haruo Amari ◽  
Hiroyuki Shimada ◽  
Takashi Matsuhisa ◽  
Ryo Fukushima ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Low Temperature ◽  
Heat Source ◽  
Heat Pump ◽  
High Efficiency ◽  
Industrial Process ◽  
Application Study ◽  
Hot Air ◽  
Heat Demand ◽  
Temperature Heat

This paper reports application study of newly developed turbo heat pump for 130 degrees Celsius (°C) water for an industrial process in an actual factory. The heat pump is characterized by high efficiency and large heat output, by using a state-of-the-art turbo compressor. The heat pump requires a low temperature heat source in order to achieve high efficiency. The heat demand is for several drying furnaces in the factory, which requires producing hot air of 120 °C. The heat exchanger was designed to produce the hot air. Experiments were conducted to confirm the performance of the heat exchanger under a reduced size of the heat exchanger. Low temperature heat sources are from both exhaust gas of the drying furnaces and that of an annealing furnace. The heat exchangers were also designed to recover heat of the exhaust gas from the two types of furnace. A thermal storage tank was prepared for the low temperature heat source, and for adjusting the time difference between the heat demand and the low temperature heat source. The size of the tank was determined by considering the schedule of furnaces operations. As a result of the present study, it was confirmed that the heat pump was able to satisfy the present heat demand while retaining high efficiency. Primary energy consumption and CO2 emission of the heat pump were calculated on the basis of the present results in order to compare them with those of the boilers.

Prediction of Non-Uniform Frost Distribution on a Fin Tube Heat Exchanger

2013 ◽  
Author(s):  
Jieun Hwang ◽  
Keumnam Cho
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Transfer Rate ◽  
Heat Pump ◽  
Transfer Rate ◽  
Volume Flow Rate ◽  
Local Data ◽  
Tube Heat Exchanger ◽  
Side Pressure ◽  
Fin Tube

Heat exchanger experiences frost on its surface when it operates below 0°C under heating condition of the heat pump. Since frost blocks air flow through the fin tube heat exchanger, it increases air-side pressure drop and deteriorates heat transfer rate of the heat exchanger. Prediction of the frost profiles on the heat exchanger is needed to minimize the unfavorable effect on the heat exchanger by frost. The present study predicts non-uniform frost distribution on the surface of fin-tube heat exchanger and shows its accuracy by comparing with measured profiles. Fin and tube heat exchanger for heat pump was considered for the frost prediction under practical refrigerant and air conditions. Non-uniform frost pattern was predicted by using segment by segment method of the heat exchanger. Heat transfer rate and exit temperature of air and refrigerant for each segment were calculated by applying ε-NTU method. Air volume flow rate in the front of the heat exchanger was decreased as frost goes on. It was utilized for the prediction of the frost formation. Numerically predicted results were compared with measured local data. They agreed within ±10.4% under the ISO 5151 condition.

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