scholarly journals Numerical Study of Hydrocarbon Charge Reduction Methods in HVAC Heat Exchangers

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4480
Author(s):  
Ehsan Allymehr ◽  
Geir Skaugen ◽  
Torsten Will ◽  
Ángel Álvarez Pardiñas ◽  
Trygve Magne Eikevik ◽  
...  
Keyword(s):  
Heat Pump ◽  
Heat Exchangers ◽  
Numerical Study ◽  
Cooling Capacity ◽  
Plate Heat ◽  
Direct System ◽  
Heating Capacity ◽  
Reduction Methods ◽  
Internal Volume ◽  
Hydrocarbon Charge

Required refrigerant charge in heat pump systems with propane is analyzed. Two systems are compared: the first a direct heat pump, with fin-and-tube heat exchangers, and the second an indirect system, with plate heat exchangers with an additional brine-to-air heat exchanger. Each system was considered to be able to work reversibly, with 5~kW design cooling capacity in summer and 8~kW design heating capacity in winter. Two separately developed simulation codes were used to calculate the required refrigerant charge and the efficiency of each of the systems. The charge was reduced by the use of microfinned tubes up to 22% in direct system reduced using microfinned tubes compared to the smooth tube. For the indirect system using specially designed plate heat exchangers with the minimum internal volume, their charge was reduced by up to 66% compared to normal plate heat exchangers.

scholarly journals Numerical Study of Flow Maldistribution in Multi-Plate Heat Exchangers Based on Robust 2D Model

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3121 ◽  
Author(s):  
Arkadiusz Brenk ◽  
Pawel Pluszka ◽  
Ziemowit Malecha
Keyword(s):  
Heat Exchangers ◽  
Numerical Study ◽  
High Heat ◽  
Pressure Balance ◽  
Plate Heat ◽  
Pressure Losses ◽  
Heat Transfer Efficiency ◽  
High Heat Transfer ◽  
Wide Range ◽  
Flow Maldistribution

Plate heat exchangers (PHE) are characterized by high heat transfer efficiency and compactness. An exploitation problem of the PHE is related to flow maldistribution, which can make part of the PHE idle, resulting in overheating and damage. Making geometrical modifications to the PHE can help reduce flow maldistribution. Modifications should be kept to a minimum, so as not to complicate the production process. There is a large number of possible geometrical modifications, which simply considers additional obstacles or stream dividers. To test all of them would be impractical and would also take a prohibitively long amount of time to obtain experimental measurements. A typical PHE is characterized by a complex system of channels. Making numerical calculations of its 3D model can be prohibitively time and resource-consuming. The present work introduces a physically consistent methodology of the transformation of a real 3D geometry to its 2D representation. Its main novelty is to assure the same pressure drop balance remains between the 3D and 2D geometries. This is achieved by a preservation of the same cumulative pressure losses in both geometries. The proposed innovative approach levels the pressure balance difference by adding properly designed local geometrical modifications. The developed methodology allowed a wide range of parameter space and various geometrical modifications to be investigated, and revealed geometrical optimizations leading to the improved performance of the PHE. To minimize the influence of other factors, an incompressible and single-phase flow was studied.

scholarly journals A Numerical Study of Small-Scale Longitudinal Heat Conduction in Plate Heat Exchangers

Energies ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. 1727 ◽  
Author(s):  
Saranmanduh Borjigin ◽  
Ting Ma ◽  
Min Zeng ◽  
Qiuwang Wang
Keyword(s):  
Heat Conduction ◽  
Heat Exchangers ◽  
Numerical Study ◽  
Small Scale ◽  
Plate Heat

Numerical study on heat transfer enhancement in capsule-type plate heat exchangers

2016 ◽  
Vol 108 ◽  
pp. 1237-1242 ◽  
Author(s):  
Yanfeng Zhang ◽  
Chen Jiang ◽  
Zonglin Yang ◽  
Yiyuan Zhang ◽  
Bofeng Bai
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Heat Exchangers ◽  
Numerical Study ◽  
Transfer Enhancement ◽  
Plate Heat ◽  
Capsule Type

Heat transfer enhancement in pillow-plate heat exchangers with dimpled surfaces: A numerical study

2019 ◽  
Vol 153 ◽  
pp. 142-146 ◽  
Author(s):  
M. Piper ◽  
A. Zibart ◽  
E. Djakow ◽  
R. Springer ◽  
W. Homberg ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Heat Exchangers ◽  
Numerical Study ◽  
Transfer Enhancement ◽  
Plate Heat

scholarly journals Performance investigation of a novel hybrid deep-dehumidification process using liquid desiccant

2019 ◽  
Vol 111 ◽  
pp. 01047
Author(s):  
Bowen Guan ◽  
Jun Liu ◽  
Xiaohua Liu ◽  
Tao Zhang ◽  
Liangliang Chen ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Heat Pump ◽  
System Performance ◽  
Air Conditioning ◽  
Cooling Capacity ◽  
Liquid Desiccant ◽  
Humidity Ratio ◽  
Air Conditioning System ◽  
Heating Capacity ◽  
Flow Through

As one of the essential dehumidification ways, liquid desiccant air conditioning system has developed quickly in recent years, especially in the deep dehumidification field. A novel hybrid deep- dehumidification system using liquid desiccant driven by heat pump is proposed in this study to simplify the arrangement of air ducts and guarantee a competitive energy efficiency. In the proposed process, the regenerator, condensing dehumidifier and liquid dehumidifier are cascaded, and the process air flow through them sequentially. Heat pump cycle is utilized in the system, where the cooling capacity of evaporator is used to cool the liquid desiccant in dehumidifier, and the heating capacity of condenser is used for desiccant regeneration. The humidity ratio of the supplied air is as low as 2.6 g/kg. No extra regeneration air or corresponding air duct are needed in the proposed process, which obviously simplifies the layout of the system. Performance of the proposed system is then analysed by numerical results. It’s indicated 17.5~29.2% energy is saved compared with the conventional deep dehumidification process with two-stage heat pump, with the outlet humidity ratio of 2.6 g/kg.

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