Modelling And Simulation OfEarth Air Tunnel Heat Exchanger
- Vol.34(10, Jan-Mar
- Pune NICMAR 2019
- 72-77p.
The Earth Air Tunnel Heat Exchanger (EATHE) is an efficient technique used to reduce the cooling load ofa building. In the past years, many researchers had developed analytical and numerical models for the analysis ofEATHE systems, but were unable to recast into design equations, and had used the trial-and-error method for the analysis. This paper focuses on modelling and simulation ofthe EATHE system for geographical conditions, with average day temperature ranging from maximum 45°C for Nagpur [21.14° N, 79.08° E]. The method to calculate the Earth's Undisturbed Temperature (EUT), and more recently developed correlations for friction factor and Nusselt number, are used to ensure higher accuracy in the calculation ofheat transfer. The developed equations can be utilized to calculate heat transfer, convective heat transfer coefficient, and length ofpipe ofthe EATHE system. A longer pipe ofsmaller diameter buried at a greater depth with lower air flow velocity results in increase in performance ofEATHE. In this paper a simple Excel based mathematical model has been developed in order to design the EATHE. This model helps in determining characteristic dimensions, air flow rate, selection ofblower and economic investments in an EATHE system.