Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Solar heat pump systems for heating applications: Analysis of system performance and possible solutions for improving system performance
Dalarna University, School of Technology and Business Studies, Energy Technology. KTH. (SERC)ORCID iD: 0000-0002-3201-8518
2017 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Solar heat pump systems (SHPs) are systems that combine solar energy and heat pumps. SHPs have been investigated for several decades and have been proven to increase the share of renewable energy and reduce electric energy demand in residential heating applications. Many solar thermal heat pump systems have become market-available in recent years; however these systems are still not widely employed in the residential sector. This is due mainly to the high initial costs (investment and installation costs) of solar thermal heat pump systems, which limits their cost-effectiveness. Enhancing cost-effectiveness of solar thermal heat pump systems is necessary for a more effective and broader market penetration.

In this thesis, solar thermal and photovoltaic systems combined with heat pumps for heating applications are treated. The overall aims of the thesis are to: 1) investigate techno-economics of SHPs and 2) investigate possible solutions for improving system performance of a reference solar thermal and heat pump system for residential heating applications.

In the first part of the thesis, the influence of climatic boundary conditions on economic performance of SHPs has been investigated by means of: a) an economic comparison of SHPs found in the relevant literature and b) system simulations of the reference solar thermal heat pump system.

In the second part of the thesis, potential solutions for improving system performance of the reference solar thermal heat pump system with limited change in system’ costs are investigated. A systematic approach was used for investigating cost-effectiveness of the system improvements in the reference system.

Based on results of the cost-effectiveness analysis, some of the investigated system improvements were chosen for being included in the design of a novel solar thermal and air source heat pump system concept. The novel system was designed for a house standard with relatively high operating temperatures (55°C/45°C) in the space heating distribution system and for high space heating demand (123 kWh/m2·year). Finally, the thesis ends with a cost-effectiveness analysis of the novel system.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2017.
National Category
Environmental Engineering
Research subject
Energy, Forests and Built Environments, MacSheep
Identifiers
URN: urn:nbn:se:du-26498ISBN: 978-91-7729-526-6 (electronic)OAI: oai:DiVA.org:du-26498DiVA: diva2:1155000
Public defence
2017-10-09, 14:26
Opponent
Supervisors
Available from: 2017-11-06 Created: 2017-11-06 Last updated: 2017-11-06Bibliographically approved
List of papers
1. Techno-economic review of solar heat pump systems for residential heating applications
Open this publication in new window or tab >>Techno-economic review of solar heat pump systems for residential heating applications
Show others...
2018 (English)In: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 81, 22-32 p.Article in journal (Refereed) Published
Abstract [en]

Solar heat pump systems (SHPs) have been investigated for several decades and have been proven to increase the share of renewable energy and reduce electric energy demand in residential heating applications. Many review articles have been published on the subject, however literature discussing the techno-economics of different solar technologies (thermal, photovoltaic and hybrid thermal/photovoltaic) in combination with heat pumps is lacking, and thus to directly compare the merits of different SHPs is not an easy task. The objectives of this study are: a) review the different system boundaries and the main performance indicators used for assessing energetic and economic performances; b) review techno-economic studies in the literature and identify which studies give enough information and are compatible enough for making an economic inter-comparison; c) present an economic inter-comparison based on the identified systems. The results show that there is a lack of studies including an economic assessment of solar photovoltaic and heat pump systems. Additionally, there are no consistent boundaries or approaches to the study structures, making comparisons between systems difficult. In conclusion, a standardized or broadly accepted definition of technical and economic performance for SHPs is needed. Despite this, the study has shown that there are clear trends for decreasing payback times for SHPs, both solar thermal (ST) and photovoltaic (PV), with decreasing heating degree-days and with increasing solar resource.

Keyword
Performance indicators, Solar heat pump systems, System boundary, System configuration
National Category
Energy Engineering
Identifiers
urn:nbn:se:du-25649 (URN)10.1016/j.rser.2017.07.041 (DOI)2-s2.0-85024839540 (Scopus ID)
Available from: 2017-07-31 Created: 2017-07-31 Last updated: 2017-11-06Bibliographically approved
2. Economic and environmental analysis of energy renovation packages for European office buildings
Open this publication in new window or tab >>Economic and environmental analysis of energy renovation packages for European office buildings
Show others...
2017 (English)In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 148, 155-165 p.Article in journal (Refereed) Published
Abstract [en]

A large share of the buildings in Europe are old and in need of renovation, both in terms of functional repairs and energy efficiency. While many studies have addressed energy renovation of buildings, they rarely combine economic and environmental life cycle analyses, particularly for office buildings. The present paper investigates the economic feasibility and environmental impact of energy renovation packages for European office buildings. The renovation packages, including windows, envelope insulation, heating, cooling and ventilation systems and solar photovoltaics (PV), were evaluated in terms of life cycle cost (LCC) and life cycle assessment (LCA) through dynamic simulation for different European climates. Compared to a purely functional renovation, the studied renovation packages resulted in up to 77% lower energy costs, 19% lower total annualized costs, 79% lower climate change impact, 89% lower non-renewable energy use, 66% lower particulate matter formation and 76% lower freshwater eutrophication impact over a period of 30 years. The lowest total costs and environmental impact, in all of the studied climates, were seen for the buildings with the lowest heating demand. Solar PV panels covering part of the electricity demand could further reduce the environmental impact and, at least in southern Europe, even reduce the total costs. © 2017 Elsevier B.V.

Keyword
Energy renovation, LCA, LCC, Office buildings, TRNSYS
National Category
Energy Engineering
Research subject
Energy, Forests and Built Environments
Identifiers
urn:nbn:se:du-25094 (URN)10.1016/j.enbuild.2017.04.079 (DOI)000404705000013 ()2-s2.0-85019454202 (Scopus ID)
Available from: 2017-06-05 Created: 2017-06-05 Last updated: 2017-11-06Bibliographically approved
3. Influence of boundary conditions and component size on electricity demand in solar thermal and heat pump combisystems
Open this publication in new window or tab >>Influence of boundary conditions and component size on electricity demand in solar thermal and heat pump combisystems
2016 (English)In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 162, 1062-1073 p.Article in journal (Refereed) Published
Abstract [en]

Solar thermal and heat pump combisystems are used to produce domestic hot water (DHW) and space heating (SH) in dwellings. Many systems are available on the market. For an impartial comparison, a definite level of thermal comfort should be defined and ensured in all systems. This work studied the influence of component size on electricity demand for a state of the art solar thermal and heat pump system. A systematic series of parametric studies was carried out by using TRNSYS to show the impact of climate, load and size of main components as well as heat source for the heat pump. Penalty functions were used to ensure that all variations provided the same comfort requirements. Two reference systems were defined and modelled based on products on the market, one with ambient air and the other with borehole as heat source for the heat pump. The results show that changes in collector area from 5 to 15 m2 result in a decrease in system electricity of between 305 and 552 kW h/year. Changes in heat exchanger size for DHW preparation were shown to give nearly as large changes in electricity use due to the fact that the set temperature in the store was changed to give the same thermal comfort in all cases. Decrease in heat pump size was shown to give a decrease in electricity use for the ASHP in the building with larger heat demand while it increased or had only a small change for other boundary conditions. Heat pump losses were shown to be an important factor highlighting the importance of modelling this factor explicitly

Keyword
Solar combisystem; Heat pump; Component size; Simulation
National Category
Environmental Engineering
Research subject
Energy, Forests and Built Environments, MacSheep
Identifiers
urn:nbn:se:du-20286 (URN)10.1016/j.apenergy.2015.10.190 (DOI)000367631000092 ()
Funder
EU, FP7, Seventh Framework Programme
Available from: 2015-11-23 Created: 2015-11-23 Last updated: 2017-11-06Bibliographically approved
4. Analysis of system improvements in solar thermal and air source heat pump combisystems
Open this publication in new window or tab >>Analysis of system improvements in solar thermal and air source heat pump combisystems
Show others...
2016 (English)In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 173, 606-623 p.Article in journal (Refereed) Published
Abstract [en]

A solar thermal and heat pump combisystem is one of many system alternatives on the market for supplying domestic hot water (DHW) and space heating (SH) in dwellings. In this study a reference solar thermal and air source heat pump combisystem was defined and modelled based on products available on the market. Based on the results of an extensive literature survey, several system variations were investigated to show the influence of heat pump cycle, thermal storage and system integration on the use of electricity for two houses in the climates of Zurich and Carcassonne. A singular economic cash flow analysis was carried out and the “additional investment limit” of each system variation was determined for a range of economic boundary conditions. This is the maximum extra investment cost for the system variant compared to the reference system that will give a break even result for a 10 year period. The results show that variations in electricity price affects the additional investment limit far more than the other economic parameters. Several of the variants show potential for achieving a cost benefit, but the potential varies a lot depending on load and climate boundary conditions. For all variants, the biggest difference in electricity savings was found for Zurich rather than in Carcassonne, which is explained by the larger heating load. However, in three cases the largest savings were for the SFH45 house despite the fact that the annual electricity use of the system is much lower than that for the SFH100 house, 3581 kW h/year compared to 8340 kW h/year. This was attributed to the fact that, in these cases, the operating level of the space heating circuit played a significant role, the SFH45 house being supplied with a 35/30 °C heating system while the SFH100 was supplied with a 55/45 °C heating system.

Place, publisher, year, edition, pages
Elsevier, 2016
Keyword
Solar combisystem; Heat pump cycle; Thermal storage; Hydraulics
National Category
Energy Systems
Research subject
Energy, Forests and Built Environments, MacSheep
Identifiers
urn:nbn:se:du-21378 (URN)10.1016/j.apenergy.2016.04.048 (DOI)000377235200050 ()
Funder
EU, FP7, Seventh Framework Programme
Available from: 2016-04-22 Created: 2016-04-22 Last updated: 2017-11-06Bibliographically approved
5. Techno-economic analysis of a novel solar thermal and air-source heat pump system
Open this publication in new window or tab >>Techno-economic analysis of a novel solar thermal and air-source heat pump system
2016 (English)Conference paper, Oral presentation with published abstract (Other (popular science, discussion, etc.))
Abstract [en]

This paper presents a techno-economic analysis of a novel solar thermal and air source heat pump system. The system was designed for relatively high operating temperatures in the space heating circuit and included the use of a heat pump with vapor injection cycle and vacuum insulation on the storage tank. The system model was validated against measurements in laboratory and simulated in TRNSYS 17. Annual simulations were performed for the combination of two climates (Carcassonne and Zurich) and two house standards (SFH45 and SFH100) and the best results were achieved for the boundary conditions the system was designed for. For those conditions (Zurich and SFH100), the novel system showed potential for being cost-effective compared to state of art solar and heat pump system. The “additional investment limit”, i.e. the maximum extra investment cost for the novel system in comparison to a state of art benchmark system that gives a break even result for a period of 10 years, varied between 827 € and 2482 € depending on electricity price. The results of a sensitivity analysis showed that variations in electricity price affected the additional investment limit far more than the other economic parameters

Keyword
solar thermal, heat pump, vapour injection
National Category
Energy Engineering
Research subject
Energy, Forests and Built Environments
Identifiers
urn:nbn:se:du-22548 (URN)
Conference
16th International Refrigeration and Air Conditioning Conference, 11-14 July 2016, West Lafayette, USA
Funder
EU, FP7, Seventh Framework Programme
Available from: 2016-07-01 Created: 2016-07-01 Last updated: 2017-11-06Bibliographically approved

Open Access in DiVA

fulltext(2398 kB)2 downloads
File information
File name FULLTEXT01.pdfFile size 2398 kBChecksum SHA-512
cff02b663f1ba23c3d7483156a664fb89eb59c2d41e01f8544d94a43facff318a6660b64718cffd86df6eea619ff1bcbc376edad842b7b387960bd409a457b1e
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Poppi, Stefano
By organisation
Energy Technology
Environmental Engineering

Search outside of DiVA

GoogleGoogle Scholar
Total: 2 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 99 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf