Impact of different improvement measures on the thermal performance of a solar collector field for district heating

Federico Bava*, Simon Furbo

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

The paper describes the impact of different measures to improve the thermal performance of a solar heating plant for district heating applications. The impact of the different measures was evaluated through a validated TRNSYS-Matlab model. The model included details such as effect of the flow regime in the absorber pipes on the collector efficiency, flow distribution in the collector field, thermal capacity of the pipes and shadows from row to row. The improvement measures included variation of the operating temperatures, accurate input to the control strategy, feedback control on the outlet temperature of the collector field, control strategy based on weather forecast and use of different heat transfer fluids. The results showed that accurate input to the control strategy improved the yearly energy output of the plant by about 3%. If accurate input is not technically or economically feasible, a feedback control on the field outlet temperature seemed to be a valid alternative. The integration of weather forecast in the control strategy did not give relevant improvements. Higher glycol concentrations in the solar collector fluid gave better results than lower concentrations, as the higher frost protection guaranteed by the former outweighed the better thermophysical properties of the latter.
Original languageEnglish
JournalEnergy
Volume144
Pages (from-to)816-825
Number of pages10
ISSN0360-5442
DOIs
Publication statusPublished - 2018

Keywords

  • Solar heating plant
  • Solar collector field
  • TRNSYS
  • Flow regime
  • Control strategy
  • Flow distribution

Cite this

@article{21d67ea89856486a9484bc5d91a7b7a0,
title = "Impact of different improvement measures on the thermal performance of a solar collector field for district heating",
abstract = "The paper describes the impact of different measures to improve the thermal performance of a solar heating plant for district heating applications. The impact of the different measures was evaluated through a validated TRNSYS-Matlab model. The model included details such as effect of the flow regime in the absorber pipes on the collector efficiency, flow distribution in the collector field, thermal capacity of the pipes and shadows from row to row. The improvement measures included variation of the operating temperatures, accurate input to the control strategy, feedback control on the outlet temperature of the collector field, control strategy based on weather forecast and use of different heat transfer fluids. The results showed that accurate input to the control strategy improved the yearly energy output of the plant by about 3{\%}. If accurate input is not technically or economically feasible, a feedback control on the field outlet temperature seemed to be a valid alternative. The integration of weather forecast in the control strategy did not give relevant improvements. Higher glycol concentrations in the solar collector fluid gave better results than lower concentrations, as the higher frost protection guaranteed by the former outweighed the better thermophysical properties of the latter.",
keywords = "Solar heating plant, Solar collector field, TRNSYS, Flow regime, Control strategy, Flow distribution",
author = "Federico Bava and Simon Furbo",
year = "2018",
doi = "10.1016/j.energy.2017.12.025",
language = "English",
volume = "144",
pages = "816--825",
journal = "Energy",
issn = "0360-5442",
publisher = "Elsevier",

}

Impact of different improvement measures on the thermal performance of a solar collector field for district heating. / Bava, Federico; Furbo, Simon.

In: Energy, Vol. 144, 2018, p. 816-825.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Impact of different improvement measures on the thermal performance of a solar collector field for district heating

AU - Bava, Federico

AU - Furbo, Simon

PY - 2018

Y1 - 2018

N2 - The paper describes the impact of different measures to improve the thermal performance of a solar heating plant for district heating applications. The impact of the different measures was evaluated through a validated TRNSYS-Matlab model. The model included details such as effect of the flow regime in the absorber pipes on the collector efficiency, flow distribution in the collector field, thermal capacity of the pipes and shadows from row to row. The improvement measures included variation of the operating temperatures, accurate input to the control strategy, feedback control on the outlet temperature of the collector field, control strategy based on weather forecast and use of different heat transfer fluids. The results showed that accurate input to the control strategy improved the yearly energy output of the plant by about 3%. If accurate input is not technically or economically feasible, a feedback control on the field outlet temperature seemed to be a valid alternative. The integration of weather forecast in the control strategy did not give relevant improvements. Higher glycol concentrations in the solar collector fluid gave better results than lower concentrations, as the higher frost protection guaranteed by the former outweighed the better thermophysical properties of the latter.

AB - The paper describes the impact of different measures to improve the thermal performance of a solar heating plant for district heating applications. The impact of the different measures was evaluated through a validated TRNSYS-Matlab model. The model included details such as effect of the flow regime in the absorber pipes on the collector efficiency, flow distribution in the collector field, thermal capacity of the pipes and shadows from row to row. The improvement measures included variation of the operating temperatures, accurate input to the control strategy, feedback control on the outlet temperature of the collector field, control strategy based on weather forecast and use of different heat transfer fluids. The results showed that accurate input to the control strategy improved the yearly energy output of the plant by about 3%. If accurate input is not technically or economically feasible, a feedback control on the field outlet temperature seemed to be a valid alternative. The integration of weather forecast in the control strategy did not give relevant improvements. Higher glycol concentrations in the solar collector fluid gave better results than lower concentrations, as the higher frost protection guaranteed by the former outweighed the better thermophysical properties of the latter.

KW - Solar heating plant

KW - Solar collector field

KW - TRNSYS

KW - Flow regime

KW - Control strategy

KW - Flow distribution

U2 - 10.1016/j.energy.2017.12.025

DO - 10.1016/j.energy.2017.12.025

M3 - Journal article

VL - 144

SP - 816

EP - 825

JO - Energy

JF - Energy

SN - 0360-5442

ER -