Natrual Convection Heat Exchangers (NCHE)
Effects of Heat Exchanger Configuration on Solar DHW Performance
The Features and Benefits of NCHE, Stratification, and Low Flow Design in Solar Thermal Systems
Benefits of External Brazed Plate Heat Exchangers in Natural Convection Flow Design
Wang, L. et all, 2007, discusses the advantages of using a side arm plate heat exchanger versus other designs:
"First the system performance is enhanced. External heat exchangers can be configured so that the potable water circulates by natural convection or thermo-siphon action that allows excellent temperature stratification to be achieved in the storage tank. With the hot water remaining in the top of the tank, its usable supply then becomes readily and more rapidly available. Second, the thermodynamic efficiency of the system is improved with the external heat exchanger configuration. The rate of the Heat transfer is directly proportional to the temperature difference between the potable water being heated and the antifreeze from the solar collectors... Third the overall cost of the system is reduced owing to the long lifetime of the external heat exchanger in the comparison with that of the solar tank... Plate heat exchangers, with their additional advantages of relative compactness, easy maintenance, and low cost are thus a natural and attractive choice for use in solar thermal applications."
Exert taken from: "Plate Heat Exchangers: Design, Applications and Performance." Wang, L. Sunden, B. Manglik, R.M., WITpress, Southampton, Boston. 2007.
Natural Convection Heat Exchangers in Solar Water Heating Systems; Theory and Experiment
Exert taken from: "Natural Convection Heat Exchangers in solar Water Heating Systems; Theory and Experiment”
M.G. Parent, TH. H. Van Der Meer, and K.G.T. Hollands
Centre for Solar Thermal Engineering, Department of Mechanical Engineering, University of Waterloo
Solar Energy Vol 45, No 1, pp 34-52, 1990