Exergy analysis of a low temperature radiant heating system

Abstract

The purpose of this study is to gain insight into the process of heating a room with a low-temperature radiant heating system and solar energy, considering energy conversion and heat transfer steps in the building (where heat is required), in the incident solar radiation (which supplies part of the heat required) and in the heating system (which provides for the additional heating needs, by using electricity from a gas-fired power plant to drive a heat pump). We applied a theoretical framework developed by Shukuya et al., to a dynamic simulation model and did numerical calculations for a room with an exterior wall, with and without a south-facing window, during a heating season in the Netherlands. The exergy analysis allows direct comparison between different energy types (e.g., heat, electricity, fuel) on a common basis, and the concept of exergy consumption is useful for expressing how and where energy is dispersed in the course of energy conversion and heat transfer steps. The results show that exergy consumption in the room (demand side) is relatively small compared to the supply side (fuel burned at the power plant and the sun reaching the ground and facade). The calculations also show that the total amount of exergy consumed during the heating season can be larger than the total amount of exergy supplied during the same period, as a result of heat storage in the building mass, and of changes in the outdoor temperature between the moment of heat storage and heat release.

Distillation Control Structure Selection for Energy‐Efficient Operations

“…It is a key aspect of providing better understanding of the process and quantifying sources of inefficiency and distinguishing quality of energy used [21][22][23] and a tool for determining the energy efficiency of a process [24,25]. Exergy represents the part of energy which can be converted into maximum useful work and is applied to establish criteria for the performance of engineering devices [26]. Unlike energy, exergy is not conserved and gets depleted due to irreversibilities in the processes [27].…”

An Evaluation of Apartment Heating System for Energy-Saving

“…Yee et al (2005) proposed a dry floor heating system using heating pipes and evaluated this system through a pilot test. Asada and Boelman (2004) analyzed energy of a low-temperature radiation heating system through a dynamic simulation model. Miura et al (2004) developed an applied system in three stages to evaluate thermal performance of a floor heating system and used this method to analyze the thermal characteristics of floors.…”

Optimal exergy control of building HVAC system

“…In recent years, use of low exergy (LowEx) system such as heat-pumps and solar collectors have spurred great interests in HVAC studies for green buildings. LowEx system and its applications have been studied before in [14][15][16][17][18][19]. For instance, in [15] LowEx system implementation is presented.…”

“…These studies can be divided into three main categories: (i) analysis of system performance, (ii) design optimization to increase efficiency, and (iii) exergy inspired control. In the first category, exergy and SLT principles are applied to analyze performance of building energy systems including building envelope [6], HVAC [5,7,10,11,[14][15][16][17]13], boilers [5,7,9], renewables integration [5,37] and energy storage systems [38][39][40]. The main objective of this category is to identify sources of inefficiency and irreversibility in the building energy systems.…”