A Numerical Investigation on a New Type Radiation Energy Supply End System

Jianbo. Ren1 , Yiping Wang1,2, Li. Zhu2*, Qunwu Huang

1 School of Chemical Engineering and Technology of Tianjin University, Tian Jin 300072, China
2 School of Architecture Tianjin University, Tian Jin 300072, China
Corresponding Author, zly13920679110@tiu. edu. cn

Abstract

A new radiation energy supply system for space heating and cooling was designed. Heat is conducted out from the metal tube loop buried underneath the corners through adjacent conductive glue layer to the wall and floor constructions, and then is dispersed inside mainly by radiation. The theoretical model of the system was established and the heat transfer process was simulated by the finite element analysis method. The analysis results show that the system has good cooling and heating performance. The space cooling and heating needs

in an energy-saving reconstructed building can be met with the 40°C heating medium in

winter and 10°C cooling medium in summer. This provides possibilities of more generous

requirements on the heating or cooling supply temperature. The heat flux from the floor and wall surfaces respectively contribute 60% and 40% to the total energy supplying in summer. The system performance is affected mainly by the tube diameter, fluid medium temperature. Keywords: Radiation energy supply; Heat transfer model; Thermal flux

1. Introduction

The building sector plays a significant role in the global energy consumption, especially in developed countries it accounts for 30%-50% of the whole energy consumption [1]. Use of radiant floor heat systems as an efficient way to achieve occupant thermal comfort in buildings with low — energy demands has increased.

There have been several studies dealing with floor heating systems in the literature. Weitzmann et al. [2] developed a two-dimensional dynamic model for simulating the floor heating systems. Lin et al.[3] conducted an experimental research on the thermal performance of under-floor electric heating system with latent heat thermal energy storage plate. They also prepared an analytical solution for this problem [4]. Laouadi [5] developed a model for analyzing radiant heating and cooling systems which can be used in building energy simulation software. Recently, Bozkir and Canbazoglu[6] studied unsteady thermal performance analysis of a room with serial and parallel duct radiant floor heating systems using hot airflow. Olesen [7] presented a comprehensive discussion on radiant floor heating systems and investigated on their underlying principles.

For the sake of reducing the investment, cooling supply is added into the floor radiation system to make it a dual-function energy supplier. Corina [8] said that radiant cooling system can be operated in any US climate with low risk of condensation, and can save on average 30% of the energy consumption and 27% of the peak demand compared to the traditional all-air system. Mumma [9][10] discussed the major concerns given about the radiant cooling system, such as condensation, cooling capacity and initial cost, and thus confirmed its relevant advantages.

In this paper, a new type radiation energy supply system for space heating and cooling was put forward. It was designed to meet the energy requirements by utilizing the heat conduction ability of both wall and floor by burying the metal tube in the corner. The paper constructed a two-

dimensional steady-state mathematical model of this system and studied this system by means of finite element method. Then influences of the diameter of embedded pipe, location of embedded pipe, water supply temperature on the temperature distribution and thermal flux on the floor and wall were investigated.