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Bales, Chris
Publications (10 of 25) Show all publications
Dermentzis, G., Ochs, F., Gustafsson, M., Calabrese, T., Siegele, D., Feist, W., . . . Bales, C. (2019). A comprehensive evaluation of a monthly-based energy auditing tool through dynamic simulations, and monitoring in a renovation case study. Energy and Buildings, 183, 713-726
Open this publication in new window or tab >>A comprehensive evaluation of a monthly-based energy auditing tool through dynamic simulations, and monitoring in a renovation case study
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2019 (English)In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 183, p. 713-726Article in journal (Refereed) Published
Abstract [en]

An energy auditing tool (PHPP) was evaluated against a dynamic simulation tool (TRNSYS) and used for the assessment of energy conservation measures in a demo case study. The comprehensive comparison of useful heating and cooling demands and loads included three building types (single-, multi-family house, and office), three building energy levels (before renovation and after renovation with a heating demand of 45 and 25 kWh/(m²·a)) and seven European climates. Dynamic simulation results proved PHPP (monthly energy balance) to be able to calculate heating demand and energy savings with good precision and cooling demand with acceptable precision compared to detailed numerical models (TRNSYS). The average deviation between the tools was 8% for heating and 15% for cooling (considering climates with a relevant cooling load only). The higher the thermal envelope quality was, i.e. in case of good energy standards and in cold climates, the better was the agreement. Furthermore, it was confirmed that PHPP slightly overestimates the heating and cooling loads by intention for system design. The renovation design of a real multi-family house was executed using PHPP as energy auditing tool. Several calculation stages were performed for (a) baseline, (b) design phase, and (c) verification with monitoring in order to calculate the corresponding heating demand. The PHPP model was calibrated twice, before and after the renovation. The necessity for tool calibration, especially for the baseline, was highlighted increasing the confidence with respect to a number of boundary conditions. In this study, PHPP was tested as an energy auditing tool aiming to be a versatile and less error-prone alternative to more complex simulation tools, which require much more expert knowledge and training. 

Keywords
Building simulation, Energy audit, Energy conservation, PHPP, Renovation, TRNSYS
National Category
Energy Engineering
Research subject
Energy, Forests and Built Environments
Identifiers
urn:nbn:se:du-29096 (URN)10.1016/j.enbuild.2018.11.046 (DOI)000456760000053 ()2-s2.0-85057811004 (Scopus ID)
Funder
EU, FP7, Seventh Framework Programme, 314461
Available from: 2018-12-17 Created: 2018-12-17 Last updated: 2019-02-14Bibliographically approved
Persson, T., Wiertzema, H., Win, K. M. & Bales, C. (2019). Modelling of dynamics and stratification effects in pellet boilers. Renewable energy, 134, 769-782
Open this publication in new window or tab >>Modelling of dynamics and stratification effects in pellet boilers
2019 (English)In: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 134, p. 769-782Article in journal (Refereed) Published
Abstract [en]

Optimizing solar and pellet heating systems can be performed by system simulations in TRNSYS. However; this requires detailed boiler models that can properly model the thermal behaviour of the boilers, such as stratification and thermal response. This study uses a combination of existing models for modelling of the pellet burner part (TRNSYS Type 210) and the water volume (TRNSYS Type 340). This approach addresses the thermal dynamics and internal stratification more accurately than other available models. The objectives of this work are to develop a method for parameter identification for the model and to validate this method and the model itself. Sets of parameters are identified for two pellet boilers and one pellet stove with a water jacket (extended room heater) and the model is validated with a realistic dynamic operation sequence. The results show that modelling of stratification is essential in order to model the true behaviour of residential boilers. The test sequences used were adequate to parameterise the models and to provide the desired accuracy, except regarding the heat losses to room air. The model shows good accuracy for a stove and one boiler, but slightly worse performance for the other boiler regarding dynamics and modelling of the stratification.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
System simulation; Modelling; Validation; Pellet boiler; Pellet stove
National Category
Energy Engineering
Research subject
Energy, Forests and Built Environments, SWX-Energi, Integrerade system för sol och biobränsle
Identifiers
urn:nbn:se:du-28900 (URN)10.1016/j.renene.2018.11.052 (DOI)000456760900067 ()2-s2.0-85057272860 (Scopus ID)
Available from: 2018-11-14 Created: 2018-11-14 Last updated: 2019-02-14Bibliographically approved
Fiedler, F., Bales, C., Persson, J., Gustavsson, M., Kovacs, P., Hemlin, O., . . . Larsson, D. (2018). Miljontak Delprojekt 2: Sammanfattning av litteratursammanställning.
Open this publication in new window or tab >>Miljontak Delprojekt 2: Sammanfattning av litteratursammanställning
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2018 (Swedish)Report (Other academic)
Publisher
p. 11
National Category
Building Technologies
Research subject
Energy, Forests and Built Environments, EMC Energi- och miljökompetenscentrum i Dalarna
Identifiers
urn:nbn:se:du-27765 (URN)
Projects
Miljontak
Funder
Swedish Energy Agency, 41857-1
Available from: 2018-06-05 Created: 2018-06-05 Last updated: 2018-06-07Bibliographically approved
Poppi, S., Sommerfeldt, N., Bales, C., Madani, H. & Lundqvist, P. (2018). Techno-economic review of solar heat pump systems for residential heating applications. Renewable & sustainable energy reviews, 81, 22-32
Open this publication in new window or tab >>Techno-economic review of solar heat pump systems for residential heating applications
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2018 (English)In: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 81, p. 22-32Article 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.

Keywords
Performance indicators, Solar heat pump systems, System boundary, System configuration
National Category
Energy Engineering
Research subject
Energy, Forests and Built Environments
Identifiers
urn:nbn:se:du-25649 (URN)10.1016/j.rser.2017.07.041 (DOI)000417070500002 ()2-s2.0-85024839540 (Scopus ID)
Available from: 2017-07-31 Created: 2017-07-31 Last updated: 2018-03-26Bibliographically approved
Gustafsson, M., Dipasquale, C., Poppi, S., Bellini, A., Fedrizzi, R., Bales, C., . . . Holmberg, S. (2017). Economic and environmental analysis of energy renovation packages for European office buildings. Energy and Buildings, 148, 155-165
Open this publication in new window or tab >>Economic and environmental analysis of energy renovation packages for European office buildings
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2017 (English)In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 148, p. 155-165Article 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.

Keywords
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
Sotnikov, A., Nielsen, C. K., Bales, C., Dalenbäck, J.-O. -., Andersen, M. & Psimopoulos, E. (2017). Simulations of a Solar-Assisted Block Heating System. In: : . Paper presented at ISES Solar World Congress 2017 - IEA SHC International Conference on Solar Heating and Cooling for Buildings and Industry 2017, Proceedings (pp. 373-383).
Open this publication in new window or tab >>Simulations of a Solar-Assisted Block Heating System
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2017 (English)Conference paper, Published paper (Refereed)
National Category
Environmental Engineering
Research subject
Energy, Forests and Built Environments
Identifiers
urn:nbn:se:du-28298 (URN)10.18086/swc.2017.06.13 (DOI)2-s2.0-85050521978 (Scopus ID)
Conference
ISES Solar World Congress 2017 - IEA SHC International Conference on Solar Heating and Cooling for Buildings and Industry 2017, Proceedings
Available from: 2018-08-13 Created: 2018-08-13 Last updated: 2018-08-13Bibliographically approved
Psimopoulos, E., Bee, E., Luthander, R. & Bales, C. (2017). Smart control strategy for PV and heat pump system utilizing thermal and electrical storage and forecast services. In: : . Paper presented at Solar World Congress 2017, Abu Dhabi, UAE, 29 Oct - 2 Nov 2017.
Open this publication in new window or tab >>Smart control strategy for PV and heat pump system utilizing thermal and electrical storage and forecast services
2017 (English)Conference paper, Oral presentation only (Refereed)
Abstract [en]

In this study, a detailed model of a single-family house with exhaust air heat pump, PV system and energy hub developed in the simulation software TRNSYS 17 is used to evaluate energy management algorithms that utilize weather and electricity price forecasts. A system with independent PV and heat pump is used as a base case. The proposed control strategy is applied to the base case to optimize the available PV electricity production using short-term weather and electricity price forecasts. The three smart and predictive control algorithms were developed with the scope to minimize final energy by the use of the thermal storage of the building, the hot water tank and electrical storage. The results show reduction of the final energy of 26.4%, increase of the self-consumption to 60% and decrease of the annual cost of 15% when using the forecast services in combination with thermal and electrical storage compared to the base case.

National Category
Energy Systems
Research subject
Energy, Forests and Built Environments, TESHP Test av solvärmepumpsystem
Identifiers
urn:nbn:se:du-27253 (URN)
Conference
Solar World Congress 2017, Abu Dhabi, UAE, 29 Oct - 2 Nov 2017
Funder
Knowledge Foundation
Available from: 2018-02-19 Created: 2018-02-19 Last updated: 2018-02-20Bibliographically approved
Psimopoulos, E., Bee, E., Luthander, R. & Bales, C. (2017). Smart control strategy for PV and heat pump system utilizing thermal and electrical storage and forecast services. In: : . Paper presented at ISES Solar World Congress 2017 - IEA SHC International Conference on Solar Heating and Cooling for Buildings and Industry 2017, Proceedings (pp. 2240-2251).
Open this publication in new window or tab >>Smart control strategy for PV and heat pump system utilizing thermal and electrical storage and forecast services
2017 (English)Conference paper, Published paper (Refereed)
National Category
Environmental Engineering
Research subject
Energy, Forests and Built Environments
Identifiers
urn:nbn:se:du-28299 (URN)10.18086/swc.2017.33.07 (DOI)2-s2.0-85050520430 (Scopus ID)
Conference
ISES Solar World Congress 2017 - IEA SHC International Conference on Solar Heating and Cooling for Buildings and Industry 2017, Proceedings
Available from: 2018-08-13 Created: 2018-08-13 Last updated: 2018-08-13Bibliographically approved
Perez de la Mora, N., Bava, F., Andersen, M., Bales, C., Lennermo, G., Nielsen, C., . . . Martínes-Moll, V. (2017). Solar district heating and cooling: A review. International journal of energy research (Print), 1-23
Open this publication in new window or tab >>Solar district heating and cooling: A review
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2017 (English)In: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, p. 1-23Article in journal (Refereed) Published
Abstract [en]

Both district heating and solar collector systems have been known and imple- mented for many years. However, the combination of the two, with solar collec- tors supplying heat to the district heating network, is relatively new, and no comprehensive review of scientific publications on this topic could be found. Thus, this paper summarizes the literature available on solar district heating and presents the state of the art and real experiences in this field. Given the lack of a generally accepted convention on the classification of solar district heating systems, this paper distinguishes centralized and decentralized solar district heating as well as block heating. For the different technologies, the paper describes commonly adopted control strategies, system configurations, types of installation, and integration. Real‐world examples are also given to provide a more detailed insight into how solar thermal technology can be integrated with district heating. Solar thermal technology combined with thermally driven chillers to provide cooling for cooling networks is also included in this paper. In order for a technology to spread successfully, not only technical but also eco- nomic issues need to be tackled. Hence, the paper identifies and describes dif- ferent

National Category
Energy Systems
Research subject
Energy, Forests and Built Environments
Identifiers
urn:nbn:se:du-26491 (URN)10.1002/er.3888 (DOI)000427120300002 ()
Projects
SHINE - SolNet
Funder
EU, FP7, Seventh Framework Programme, 2012‐317085
Available from: 2017-11-02 Created: 2017-11-02 Last updated: 2018-04-05Bibliographically approved
Bales, C. & Lorenz, K. (2016). Application of Polysun in Teaching Courses in Sweden and in the PhD Program SHINE. In: SIGES Internationale Konferenz zur Simulation gebäudetechnischer Energiesysteme: . Paper presented at SIGES Internationale Konferenz zur Simulation gebäudetechnischer Energiesysteme, Winterthur, Schweiz, 8-9 september 2016 (pp. 90-95).
Open this publication in new window or tab >>Application of Polysun in Teaching Courses in Sweden and in the PhD Program SHINE
2016 (English)In: SIGES Internationale Konferenz zur Simulation gebäudetechnischer Energiesysteme, 2016, p. 90-95Conference paper, Published paper (Other academic)
Keywords
Solar thermal, education, simulation
National Category
Energy Engineering
Research subject
Energy, Forests and Built Environments, SHINE; Energy, Forests and Built Environments
Identifiers
urn:nbn:se:du-23370 (URN)
Conference
SIGES Internationale Konferenz zur Simulation gebäudetechnischer Energiesysteme, Winterthur, Schweiz, 8-9 september 2016
Projects
SHINE
Funder
EU, FP7, Seventh Framework Programme, 317085
Available from: 2016-11-15 Created: 2016-11-15 Last updated: 2016-11-16Bibliographically approved
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