Express Method for Assessing Optimality of Industrial Heat Exchangers for Adsorption Heat Transformation

Abstract

In this work, four radiators with different core geometries were tested using a wind tunnel. The values of the global heat transfer coefficient (UA = 5 ÷ 65 W/K) were measured depending on the flow of air and water. The obtained UA values correlate well with the data of sorption experiments described in the literature. The found correlations between the Nusselt and Reynolds numbers made it possible to propose an algorithm for ranging commercial air radiators for the use in adsorption heat transformers. It is shown that the use of a wind tunnel can serve as an effective tool for express assessment of the prospects of using air radiators for adsorption heat conversion without destroying radiators or their direct testing in a complex adsorption installation requiring vacuum maintenance.

Modeling of finned flat tube heat exchangers and search of Nusselt-Reynolds numbers correlations

“…At the same time, it can be seen that the heat transfer coefficients are strongly dependent on the air flow rate. This is in agreement with both theoretical considerations [33] and previously observed experimental results [36]. This makes it possible to find the correlations between the Nusselt and Reynolds numbers based on the experimental data obtained for the model heat exchangers considered in this paper.…”

“…The experimentally found UA and maximal power transferred from sorbent to water for the tested Hex were very close to theoretically values of the same parameters calculated according to (1,2). In [35] eight commercial radiators were considered and detailed information on their cores' geometry was comprehensively analysed. On the base of information about abovementioned Hexes' geometry UA coefficient for heat exchangers with the fixed volume were estimated.…”

“…Thus, to find the best heat exchanger for a given adsorption cycle, relatively simple and time-efficient experiments can be performed if the properties of the adsorbent are known. For example, in [35] it was shown that heat transfer coefficient h2 for desorption stage of daily heat storage cycle is as high as h2 = 125 W/(m 2 •K). Which radiator will be better for this cycle and how much higher will be its global heat transfer coefficient UA?…”

“…The question is: "Will be the Hex with highest value of UA for air-liquid engine cooling process (among a number of commercial radiators) optimal for adsorption heat transformation?". In [36] it was shown that: "Yes, testing of commercial radiators in wind tunnel can give information about their prospects for AHT". The heat exchangers considered in abovementioned article were manufactured from commercially produced radiators.…”

Composites Based on CaCl2-CaBr2 Salt System for Adsorption Applications: Designing the Optimal Sorbent for Gas Drying and Air Conditioning

“…Paper [55] discusses the possibility of optimizing the geometry of a finned flat tube (FFT) heat exchanger (Figure 8) for the application of adsorption cooling by varying the distance between the primary and secondary heat-removing elements. A real heat exchanger with a geometry close to the optimal geometry calculated in [55] is presented in [56]. Let us estimate the amount of sorbent based on a binary salt system that can be loaded into such a heat exchanger (Table 4).…”