3 research outputs found
Feasibility study of a plastic helical coil heat exchanger for a domestic water storage tank
The main goal of this study is to investigate whether it is possible to use a polymeric helical coil heat exchanger as an alternative to conventional metallic helical coil. More specifically this work focuses on a helical coil design for a domestic water storage tank application. Corrosion and fouling resistance, scarcity of the materials, low weight and cost are the driving forces to consider designing polymeric heat exchangers rather than metallic heat exchangers. However, simply replacing the metallic material by the polymer material and applying the traditional design methods used for metallic heat exchangers do not lead to an acceptable design. If one wants to design a good polymer heat exchanger, heat transfer and structural problems have to be solved first. In addition, the pressure drop limitation should not be neglected. In order to reach this goal, a model is developed to predict the optimal design of a helical coil heat exchanger immersed in the water storage tank for a certain water mass flow rate and temperature. This design compensates for the low thermal conductivity and strength of the polymer.Papers presented to the 12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Costa de Sol, Spain on 11-13 July 2016
Parametric study of a triangular cross corrugated plate
The main goal of this study is to investigate the influence of apex angle and Reynolds number on the thermal hydraulic performance of triangular cross corrugated plates. More specifically this work focuses on triangular cross corrugated plate with the orientation angle of 90°. The computational fluid dynamics (CFD) method is used to conduct, three-dimensional simulations for 426 < Re < 2021 in a periodic unitary cell. The Reynolds Stress model is used as the turbulence model. The numerical results are in a very good agreement with experimental results correlation. They show deviations between 0.8 – 4.84 %. The highest thermal performances are achieved by the both apex angle of 120° and 90°. The lowest thermal performance is observed by the apex angle of 55°. The heat exchanger with the apex angle of 90° has the highest friction factor. For the Reynolds number lower than 1300, the apex angle of 120° shows the lowest friction factor. However for the Reynolds number higher than 1300, the apex angle of 55° shows the highest hydraulic performance.Papers presented at the 13th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Portoroz, Slovenia on 17-19 July 2017 .International centre for heat and mass transfer.American society of thermal and fluids engineers
Plastic helical coil heat exchanger as an alternative for a domestic water storage tank
A reduction in weight and cost of a domestic hot water
storage vessels is an interesting case for the industry, that can be
reached by an alternative material of the helical coil heat
exchanger inside them. The goal of the present study was to
design a fully polymer solar boiler demonstrator and to explore
its thermal performance in the low pressure and low temperature
conditions. The metal coil of the conventional solar boiler for
domestic usage was replaced by a plastic tube and the heat
transfer behavior of helically coiled smooth plastic tube heat
exchanger was investigated experimentally. The heat exchanger
is placed in the middle of the tank in two parallel coils that fill
almost whole height of the vessel in order to achieve maximal
surface area. The water inside the tank was heated by circulating
in closed loop with heater to achieve constant initial temperature
across the whole volume of the vessel. When reached, the
heating was stopped and a cold water of the tap temperature
started to flow inside the polymeric tube. All the required
parameters like inlet and outlet temperatures of tube-side and
stratified temperatures in fifteen different points, flow rate of
fluids and pressure drop were measured using appropriate
instruments. The test runs were performed for different initial
temperatures inside the tank ranging from 30-60°C from which
the overall heat transfer coefficient and thermal resistances were
calculated. The validity of obtained results was compared with
the numerical simulation and the experimental results on the
initial metallic tube.Papers presented at the 13th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Portoroz, Slovenia on 17-19 July 2017 .International centre for heat and mass transfer.American society of thermal and fluids engineers