Pipe Sizing for Novel Heat Distribution Technology

Helge Averfalk,Sven Werner,Fredric Ottermo

doi:10.3390/en12071276

Abstract

This paper assesses pipe sizing aspects for previously proposed, novel, low heat distribution technology with three pipes. Assessment issues include heat loss, pressure loss, and pipe sizing for different typical pipe configurations. This assessment has been provided by the analysis of a case area with single-family houses. Concerning heat loss, the proposed three-pipe solutions have the same magnitude of heat loss as conventional twin pipes, since lower return temperatures compensate for the larger heat loss area from the third pipe. Regarding pressure loss, the main restriction on the size of the third pipe is limited to the pressure loss in the third pipe. Thermostatic valves to manage the flow rate of the third pipe are advocated, since alternative small pumps have not been found to be commercially available. The pipe sizing recommendation is that the third pipe for recirculation purposes can be two to three standard pipe sizes smaller than the corresponding supply and return pipe, if no prosumer is connected in the heat distribution network.

Highlights

Utilisation of abundant, renewable and societal excess heat sources to supply a low exergetic heat demand can drive the energy transition towards improved resource efficiency, and provide energy system synergies simultaneously [1]
The results indicate that the annual heat loss from the novel heat distribution technology is on the same order of magnitude as an ordinary twin-pipe system when the third pipe is displaced 3 to 4 times
The impossible cases are not considered in the final recommendations, since the results indicate that 2 to 3 downward displacements are recommended to maintain the minimum recirculation flow rate in the recirculation pipe

Summary

Introduction

Utilisation of abundant, renewable and societal excess heat sources to supply a low exergetic heat demand can drive the energy transition towards improved resource efficiency, and provide energy system synergies simultaneously [1]. Different pathways to obtain a future decarbonised EU energy system have been analysed; one such analysis finds that increased implementation of district heating achieves the cost effective reduction of carbon dioxide emissions [5]. The issue of global warming caused by greenhouse gas emissions and the strengthening of improved security of the energy supply results in challenges for the current heat recovery infrastructure. Current district heating systems have been developed with access to readily available, high temperature heat sources, prominently fossil in origin, with high customer heat demands, which allow significant space for inefficiency. This will not be the future case, due to climate change and energy efficiency

Results

Discussion

Conclusion