HVAC Systems Heat Recovery with Multi-Layered Oscillating Heat Pipes

Kabát, Juraj; Gužela, Štefan; Peciar, Peter

doi:10.2478/scjme-2019-0004

Cited by 4 publications

(4 citation statements)

References 17 publications

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“…Experimental tests under different conditions were conducted and compared with simulations using Honeywell's UniSim ® Design Suite software. The results suggest that the ML-OHPHE could effectively serve as a passive heat transfer device for HVAC heat recovery [40].…”

Section: Introductionmentioning

confidence: 91%

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Study of Heat Recovery Equipment for Building Applications

Popescu,

Catalina

2023

Buildings

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Nowadays, heat exchangers find widespread use across various applications in different fields, particularly in the field of heat recovery. This paper provides a detailed explanation of a plate heat exchanger counter-flow model developed in Simulink/Matlab. Water was employed in simulations for both circuits, although the thermal properties of other fluids can be investigated by modifying them. The “Tanks in series” method was used for simulation purposes. The developed model enables users to explore the impact of various parameters on heat exchanger functionality, such as altering the number of plates, the material or thickness of the plates, and the nature of thermal agents (gaseous or liquid). These models play a crucial role not only in simulating and sizing heat exchangers but also in achieving parametric optimization. Parameter variations can be employed to examine the operation of existing equipment under conditions different from their design specifications. The Simulink/Matlab proposed model, featuring a variable number of finite volumes to ensure high accuracy, was compared to the classical design method for plate heat exchangers. The results revealed good accuracy, with relative errors for heat transfer rate remaining below 2.6%. This research also considered the study of the number of finite volumes necessary for achieving accurate results. For the 40 finite volumes model, the relative error for heat transfer rate is less than 10%. Dividing the mesh into 50 finite volumes along the fluid flow direction resulted in relative errors ranging from 1.6% to 1.7%, indicating that a finer mesh was not necessary. To validate the conceived model, experimental data from the literature were compared. The relative errors for heat transfer rate between the Matlab/Simulink model’s results and experimental data ranged from 1.58% to 11.92%, demonstrating a strong agreement between the conceived model and the experimental values.

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Section: Introductionmentioning

confidence: 91%

“…Recent studies explore the heat performance of a Multi-Layered Oscillating Heat Pipe Heat Exchanger (ML-OHPHE) for heat recovery in HVAC systems [40]. Experimental tests under different conditions were conducted and compared with simulations using Honeywell's UniSim ® Design Suite software.…”

Section: Introductionmentioning

confidence: 99%

Study of Heat Recovery Equipment for Building Applications

Popescu,

Catalina

2023

Buildings

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“…Kapilan et.al [14] performed a CFD analysis is used to analyse the evaporative cooling system in a refrigerator and air-conditioning system. KABÁT Juraj et.al [15] performed an experiment on heating, ventilation and air conditioning systems and conclude that the onset of stable oscillations of the working fluid heavily increases the heat transfer performance compared to the empty heat exchanger.so heat exchanger also plays an important role in improving the performance of a refrigeration system.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic Analysis of Low GWP Refrigerant Mixtures in a Refrigerator as Replacement to R-134A

Hasheer

Srinivas²

2019

Strojnícky Časopis - Journal of Mechanical Engineering

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Chlorofluorocarbons and hydro chlorofluorocarbons (HCFCs) are replaced by hydroflourocarbons (HFCs) which is not harmful to the ozone layer. However, few of HFCs have a relatively high global warming potential (GWP) and are subject to further examination due to growing concerns about global climate change. The goal now is to find the next generation of environmentally sustainable work fluids with an insignificant direct environmental impact in terms of ozone depletion and global warming potential. This document introduces the mixture of low-GWP refrigerants like R440A, R430A, R1234ze (E)/152a (50:50 by mass), R290/600a (40/60), R290/600(60/40), R290/600(50/50), ARM 42,ARM 42a and AC5 are used to replace R-134a in a domestic refrigeration system without doing any modifications to the system. The performance of the refrigerator was observed in terms of volumetric cooling capacity, blower discharge temperature, and coefficient of performance, refrigeration effect and energy consumption of a blower.

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“…Jouhara and Althoughmmon shown that employing heat pipe-based free cooling systems in HVAC systems could result in potential energy savings of up to 75% [2,3]. Kabat, Guzela, and Peciar, get the best heat exchanger performance from the heat pipe at a 50% fill ratio [4].…”

mentioning

confidence: 99%

Untitled

2023

Jurnal Polimesin

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The heat pipe (HP) is a fundamental heat transfer component frequently utilized for energy recovery in heating, ventilation, and air conditioning (HVAC). However, a heat pipe transmits heat from the hot side (evaporator) to the cold side (condenser), resulting in a temperature difference on both sides. There are numerous methods for measuring heat pipe performance. Using the temperature difference between the evaporator and condenser, the performance characteristics may be evaluated. The objective of this study is to compare the thermal performance of thermosiphon and commercial wick heat pipes (WHP) utilizing water as the working fluid and varying temperatures between the evaporator and condenser. The copper thermosiphon and commercial wick heat pipe had a diameter of 10 mm, a length of 800 mm, and a vacuum pressure of 5000 Pa. The filling ratios range between 30% and 50%, and it was evacuated at a pressure of 5000 Pa; the hot water temperatures at the evaporator were 30, 50, 70, and 90 ºC. Temperature was steadily increased every 30 minutes, and variations were observed at multiple places, including hot water, evaporator, and condenser wall. The average difference in temperature between the WHP and thermosiphon was around 0.6 degrees Celsius. The decreased temperature difference (T) indicates that the heat pipe is performing well. In addition, if the temperature difference is very great, the HP will dry up, therefore the WHP performs better than the thermosiphon.

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HVAC Systems Heat Recovery with Multi-Layered Oscillating Heat Pipes

Cited by 4 publications

References 17 publications

Study of Heat Recovery Equipment for Building Applications

Study of Heat Recovery Equipment for Building Applications

Thermodynamic Analysis of Low GWP Refrigerant Mixtures in a Refrigerator as Replacement to R-134A

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