A criterial analysis of the effectiveness of air-to-air heat exchangers with periodic change of airflow direction

Borodulin, V. Yu; Низовцев, М. И.

doi:10.1016/j.applthermaleng.2017.11.126

Cited by 14 publications

(4 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Also, for the double-core exchanger developed by Tempeff (Tempeff North America 2020), the supply side sensors are exposed to a sawtooth profile while those on the exhaust side experience semi-sawtooth profile. For the single-core exchanger or room-based energy recovery exchanger (ventilator) (Borodulin and Nizovtsev 2018), as shown in Table 1, the sensors at the FBR supply and exhaust sides are exposed to a semi-sawtooth profile that is labeled exchanger sensor in Table 1.…”

Section: Fbr Configurations and Outlet Property Profilesmentioning

confidence: 99%

“…Different types of AAEEs are available in the market, including fixed-plate exchangers, heat pipes, energy/heat wheels, fixed-bed regenerators (FBRs), and runaround membrane exchangers (ASHRAE 2012;Diao et al 2014;Wemhoener et al 2016;Lowenstein 2008;Fan et al 2006). Among these AAEEs, FBRs are gaining more interest nowadays for energy recovery in HVAC applications (Borodulin and Nizovtsev 2018;Nizovtsev et al 2016;Chang, Liang, and Chen 2018;Cerrah, McCague, and Bahrami 2020;Ramin, Krishnan, and Simonson 2019;), due to their high ratio of energy transfer area to volume, which leads to high effectiveness. In the literature, they are widely referred to as single-core regenerators, double-core regenerators (CSA Group 2018), room-based ventilators (Nizovtsev et al 2016;Aristov, Mezentsev, and Mukhin 2006), reversing-flow regenerators (CSA Group 2018), and exchangers with a periodic change in the flow direction (Chang, Liang, and Chen 2018;Chang et al 2013;2017).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A transient numerical model for desiccant-coated fixed-bed regenerators and compensation for transient sensor errors

Ramin

Krishnan

Gurubalan

et al. 2022

Science and Technology for the Built Environment

View full text Add to dashboard Cite

Desiccant-coated fixed-bed regenerators (FBRs) can achieve high effectiveness due to high ratio of energy transfer area to volume, and therefore, they are favourable air-to-air energy recovery exchangers for HVAC systems. However, unlike other types of energy recovery exchangers, the air properties (i.e., temperature and humidity) at the outlet of FBRs vary with time. The variations in outlet airflow properties can cause errors in measurements because the measurements include the FBR and sensors transient responses. In this paper, a numerical model is developed to evaluate the performance of desiccant-coated FBRs and their transient operation. The model consists of an exchanger model (FBR model) and sensor (temperature and humidity) models to distinguish the actual performance of the FBR alone from the measured performance, which includes both the FBR and the sensor's response. The model is validated with experimental measurements and available results in the literature. The model can decouple the measured response of the FBR and sensors to predict the FBR performance. This paper's main contribution is an insight into the complex heat and mass transfer processes in desiccant-coated FBRs and measurement sensors. The results of this paper could be used to provide practical recommendations for humidity measurements of different types of desiccant-coated FBRs developed for HVAC applications. Furthermore, the measurement requirements in the current testing standards (ASHRAE 84 and CSA C439-18 standards) for FBRs are examined. Recommendations from this paper could be implemented in future versions of these standards.

show abstract

Section: Fbr Configurations and Outlet Property Profilesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A transient numerical model for desiccant-coated fixed-bed regenerators and compensation for transient sensor errors

Ramin

Krishnan

Gurubalan

et al. 2022

Science and Technology for the Built Environment

View full text Add to dashboard Cite

show abstract

“…Energy wheels have been extensively studied for energy recovery in HVAC applications [2,[5][6][7][8][9], and FBRs have been used for heat recovery in high-temperature applications such as glass furnaces, coke ovens, and open-hearth steel furnaces [10][11][12][13]. In recent times, FBRs have been attracting increasing attention for energy recovery in HVAC applications due to their high effectiveness [1,[14][15][16][17][18]. Typical heating and cooling periods of FBRs are about 20 minutes for glass furnace applications [12,13], whereas, in the HVAC industry, a shorter period duration of 15-120 seconds is required [18][19][20].…”

Section: Introductionmentioning

confidence: 99%

“…Krishnan et al [20] reported significant deviations in the experimental determination of the effectiveness of FBRs due to sensor transient, especially at the shorter operating cycles (15 seconds). In recent studies of FBRs for HVAC applications [1,16,18], the mathematical models have been used to predict the effectiveness, but the initial 2 Numerical model for the FBR and temperature sensor…”

Section: Introductionmentioning

confidence: 99%

A transient numerical model for sensible fixed-bed regenerator in HVAC applications

Ramin

Krishnan

Gurubalan

et al. 2021

International Journal of Heat and Mass Transfer

View full text Add to dashboard Cite

Determination of the sensible heat effectiveness and pressure loss of a rotary regenerative heat exchanger using CFD

Zmrhal

Zelensky²,

Boháč³

et al. 2023

Build. Simul.

View full text Add to dashboard Cite

The paper presents a new method to determine the sensible effectiveness and pressure loss of rotary regenerative heat exchangers using computational fluid dynamics (CFD). It is based on CFD simulations of a single thermal wheel microchannel with a small cross-sectional area and thin walls, with cyclic inlet and outlet boundary conditions. Two unique measurement set-ups were designed and built for the experimental measurement of the heat exchanger characteristics. Five different types of thermal wheels were manufactured, measured, and simulated in ANSYS Fluent. All wheels achieve an effectiveness greater than 73% under certain (air flow) conditions, which is the minimum effectiveness required by Ecodesign (in the EU). For the examined exchangers, the effectiveness ranges from 66.5% to 83.3%, depending on the boundary conditions and geometric parameters of the rotors. The highest sensible effectiveness is achieved by heat exchangers with the largest heat exchange surface Ac; on the other hand, these wheels have the largest pressure loss. The paper discusses the use of a simplified ε-NTU correlation model for the HVAC systems (typically C* = 1). The correlation model and CFD results were compared and found to be different from each other. The results of the CFD simulation were compared with measurements to prove that the proposed simulation method can predict the behaviour of the real heat exchanger as a whole. It was demonstrated that the sensible effectiveness and pressure loss of the rotary heat exchanger predicted by the CFD simulations correspond well to the measured values within the measurement uncertainty ±1.3%. The proposed method can be used for the comparison of different rotary regenerative heat exchangers before their manufacturing and for verification that they meet the EU Ecodesign requirements set by the current legislation. It reduces the cost of the initial optimisation and testing of new designs.

show abstract

A criterial analysis of the effectiveness of air-to-air heat exchangers with periodic change of airflow direction

Cited by 14 publications

References 24 publications

A transient numerical model for desiccant-coated fixed-bed regenerators and compensation for transient sensor errors

A transient numerical model for desiccant-coated fixed-bed regenerators and compensation for transient sensor errors

A transient numerical model for sensible fixed-bed regenerator in HVAC applications

Determination of the sensible heat effectiveness and pressure loss of a rotary regenerative heat exchanger using CFD

Contact Info

Product

Resources

About