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BETA
Östin, Ronny, Universitetslektor
Alternative names
Biography [swe]

Fokus för min forskning är energieffektivisering i bostäder och lokaler baserat på omfattande realtids-mätningar och därpå baserade analyser.

Publications (10 of 26) Show all publications
Östin, R. & Nair, G. (2019). Energy performance and lessons learned from detailed measurement of a passive house preschool in cold climate. In: Is efficient sufficient?: eceee 2019 Summer Study on energy efficiency: Abstracts. Paper presented at European Council for an Energy Efficient Economy (ECEEE), France, June 3-8, 2019. (pp. 1433-1442). European Council for an Energy Efficient Economy (ECEEE)
Open this publication in new window or tab >>Energy performance and lessons learned from detailed measurement of a passive house preschool in cold climate
2019 (English)In: Is efficient sufficient?: eceee 2019 Summer Study on energy efficiency: Abstracts, European Council for an Energy Efficient Economy (ECEEE), 2019, p. 1433-1442Conference paper, Published paper (Refereed)
Abstract [en]

Public passive house buildings are rare in high northern latitudes. This study reports on extensive measurements and evaluations of the most northerly (640 N) built passive house preschool in Sweden. The two storied preschool, built in 2014, has a total heated floor area of 1407 m2. The building was certified according to the international passive house standard. The building has several smart solutions such as demand controlled ventilation of individual rooms and automatic solar shading system.

Energy measurements conducted during 2017-2018 showed that the preschool annually uses 44.4 kWhm-2, which is approximately 25 % lower than the passive house requirement for energy demand. However, the annual specific space heating requirement of 15 kWhm-2 and the peak heat power demand of 10 Wm-2 were not fulfilled. This non-compliance was mainly due to excessive ventilation during the heating season which was found to have 2.7 times higher air changes than the requirement in the Swedish building code. Furthermore, the building was found to be over heated from the sun during several occasions in a year. For example, excessive indoor air temperatures in the range 28 – 31°C were found during summer.

The study revealed that the default winter operation by turning off the ventilation system during nights and weekends is continued in other seasons as well. This practice was not a “smart” approach for the air handling units as it was found to be one of the reasons for high indoor temperatures during non-winter months. Also, a mismatch between the operation of the automatic shading device and the ventilation control units was noted.

The investigation shows that smart technical solutions in buildings may not be able to deliver its’ promised results if such systems are not monitored, adjusted and carefully evaluated. The paper identifies areas that need attention to ensure that a public building built to passive house standard actually deliver the energy efficiency it promises.

Place, publisher, year, edition, pages
European Council for an Energy Efficient Economy (ECEEE), 2019
Series
Ecee Summer Study Proceedings, ISSN 1653-7025, E-ISSN 2001-7960
Keywords
passive houses, energy measurement, building energy certification, energy efficiency action plans
National Category
Energy Systems
Identifiers
urn:nbn:se:umu:diva-159707 (URN)978-91-983878-0-3 (ISBN)978-91-983878-1-0 (ISBN)
Conference
European Council for an Energy Efficient Economy (ECEEE), France, June 3-8, 2019.
Available from: 2019-06-04 Created: 2019-06-04 Last updated: 2019-06-13Bibliographically approved
Puttige, A. R., Andersson, S., Östin, R. & Olofsson, T. (2019). Method to estimate the ground loads for missing periods in a monitored GSHP. In: EUROPEAN GEOTHERMAL CONGRESS 2019: THE HAGUE, 11-14 JUNE 2019. Paper presented at European Geothermal Congress, The Hague, The Netherlands, June 11-14, 2019.
Open this publication in new window or tab >>Method to estimate the ground loads for missing periods in a monitored GSHP
2019 (English)In: EUROPEAN GEOTHERMAL CONGRESS 2019: THE HAGUE, 11-14 JUNE 2019, 2019Conference paper, Poster (with or without abstract) (Other academic)
Abstract [en]

Monitoring a ground source heat pump can provide important insights into its working, but to study the behaviour of the borehole heat exchanger (BHE) we require monitored data for the whole period of operation. In practice, the monitored data often has periods of missing data. We propose a method to estimate the load during the periods of missing data based on the fluid temperature after that period. The method determined the missing load with negligible error, for the case of a BHE that behaves exactly like the model describing it. A sensitivity analysis showed that the estimated load is highly sensitive to errors in measured load and fluid temperature. The method was applied to a real monitored BHE, the magnitude of estimated loads were unreasonably high, but the overall deviation between the measured and simulated values of fluid temperature decreased. Therefore, the high magnitude of missing load compensates for the lack of agreement between the model and the measured data.

Keywords
ground source heat pump, borehole heat exchanger, monitored, missing loads.
National Category
Energy Engineering
Identifiers
urn:nbn:se:umu:diva-160966 (URN)
Conference
European Geothermal Congress, The Hague, The Netherlands, June 11-14, 2019
Available from: 2019-06-26 Created: 2019-06-26 Last updated: 2019-06-27Bibliographically approved
Puttige, A. R., Andersson, S., Östin, R. & Olofsson, T. (2019). Method to estimate the ground loads for missing periods in a monitored GSHP. In: European Geothermal Congress 2019: . Paper presented at European Geothermal Congress 2019 Den Haag, The Netherlands, June 11-14, 2019.
Open this publication in new window or tab >>Method to estimate the ground loads for missing periods in a monitored GSHP
2019 (English)In: European Geothermal Congress 2019, 2019Conference paper, Poster (with or without abstract) (Other academic)
Abstract [en]

Monitoring a ground source heat pump can provide important insights into its working, but to study the behaviour of the borehole heat exchanger (BHE) we require monitored data for the whole period of operation. In practice, the monitored data often has periods of missing data. We propose a method to estimate the load during the periods of missing data based on the fluid temperature after that period. The method determined the missing load with negligible error, for the case of a BHE that behaves exactly like the model describing it. A sensitivity analysis showed that the estimated load is highly sensitive to errors in measured load and fluid temperature. The method was applied to a real monitored BHE, the magnitude of estimated loads were unreasonably high, but the overall deviation between the measured and simulated values of fluid temperature decreased. Therefore, the high magnitude of missing load compensates for the lack of agreement between the model and the measured data.

Keywords
ground source heat pump, borehole heat exchanger, monitored, missing loads
National Category
Energy Engineering
Identifiers
urn:nbn:se:umu:diva-161118 (URN)
Conference
European Geothermal Congress 2019 Den Haag, The Netherlands, June 11-14, 2019
Available from: 2019-06-27 Created: 2019-06-27 Last updated: 2019-06-28Bibliographically approved
Brembilla, C., Östin, R., Soleimani-Mohseni, M. & Olofsson, T. (2019). Paradoxes in understanding the Efficiency Factors of Space Heating. Energy Efficiency, 12(3), 777-786
Open this publication in new window or tab >>Paradoxes in understanding the Efficiency Factors of Space Heating
2019 (English)In: Energy Efficiency, ISSN 1570-646X, E-ISSN 1570-6478, Vol. 12, no 3, p. 777-786Article in journal (Refereed) Published
Abstract [en]

Efficiency factors are here defined as the thermal energy performance indicators of the space heating. Until recently, the efficiency factors were assumed as one value for space heating located in any climate. This study addresses the problem of how the outdoor climate affects the efficiency factors of a space heating equipped with 1D model of hydronic floor heating. The findings show how the efficiency factors, computed with two numerical methods, are correlated with the solar radiation. This study highlights the paradoxes in understanding the results of efficiency factors analysis. This work suggests how to interpret and use the efficiency factors as a benchmark performance indicator.

Place, publisher, year, edition, pages
Springer, 2019
Keywords
Efficiency factors, Space heating, Accuracy 1D model of hydronic floor heating, Outdoor climate, Performance indicator, Solar radiation, Benchmark, Linear regression model
National Category
Building Technologies
Research subject
engineering science with specialization in microsystems technology
Identifiers
urn:nbn:se:umu:diva-149931 (URN)10.1007/s12053-018-9692-y (DOI)000461106400015 ()2-s2.0-85049553312 (Scopus ID)
Projects
Reliability and robustness of efficiency factors theory of the space heating equipped with hydronic technologies
Available from: 2018-06-29 Created: 2018-06-29 Last updated: 2019-04-04Bibliographically approved
Brembilla, C., Östin, R. & Olofsson, T. (2018). Predictions' robustness of one-dimensional model of hydronic floor heating: novel validation methodology using a thermostatic booth simulator and uncertainty analysis. Journal of Building Physics, 41(5), 418-444
Open this publication in new window or tab >>Predictions' robustness of one-dimensional model of hydronic floor heating: novel validation methodology using a thermostatic booth simulator and uncertainty analysis
2018 (English)In: Journal of Building Physics, ISSN 1744-2591, E-ISSN 1744-2583, Vol. 41, no 5, p. 418-444Article in journal, Editorial material (Refereed) Published
Abstract [en]

Hydronic floor heating models provide predictions in estimating heat transfer rates and floor surface temperature. Information on the model performance and range of validity of its results are often lacking in literature. Researchers have to know the accuracy and robustness of the model outcomes for performing energy and climate comfort calculations. This article proposes a novel validation methodology based on the uncertainty analysis of input data/parameters of one-dimensional model of hydronic floor heating tested in a thermostatic booth simulator and compared with experimental measurements. The main results are: (1) prediction accuracy between 0.4% and 2.9% for Tf and between 0.7% and 7.8% for qup when the serpentine has tube spacing (p) of 0.30 m, (2) prediction accuracy between 0.5% and 1.4% for Tf and between 8.7% and 12.9% for qup with p = 0.15m and (3) Tfld mostly affects predictions with oscillations between 6.2% and 2.2% for qup. This model provides robust and reliable predictions exclusively for qup when p = 0.30m.

Place, publisher, year, edition, pages
Sage Publications, 2018
Keywords
One-Dimensional model of hydronic floor heating, thermostatic booth simulator, validation methodology, uncertainty bands, differential sensitivity analysis, robustness of model's predictions
National Category
Building Technologies
Research subject
Physics
Identifiers
urn:nbn:se:umu:diva-136486 (URN)10.1177/1744259117721002 (DOI)000429862600002 ()
Available from: 2017-06-19 Created: 2017-06-19 Last updated: 2018-09-21Bibliographically approved
Ohlsson, K. A., Östin, R. & Olofsson, T. (2018). Sol-air thermometer measurement of heat transfer coefficient at building outdoor surface. Energy Procedia, 132, 357-362
Open this publication in new window or tab >>Sol-air thermometer measurement of heat transfer coefficient at building outdoor surface
2018 (English)In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 132, p. 357-362Article in journal (Refereed) Published
Abstract [en]

Heat flow measurement with a heat flow meter is a standardized method (ISO 9869-1) to estimate thermal transmittance (U-value) of a building element. The heat flow meter is a thin plate mounted on top of the surface of the element, and measures the heat flux q through the plate. The measured q is the product of the difference in temperatures between exterior and interior environment, and the U-value. The heat transferred from the element is based on the radiant and the convective heat transfer.

ISO 9869-1 specifies that the environment temperature Te “is a notional temperature" and it "cannot be measured directly” (section A.3.1). The air temperature Ta is proposed as a reasonable approximation for the indoor environment, while overcast conditions and absence of significant solar radiation are specified conditions for replacing Te with Ta for the exterior environment.

The sol-air thermometer (SAT) measures the sol-air temperature Tsa, i.e. the equivalent temperature of the convective and the radiative environment. In the absence of solar radiation, Te = Tsa. SAT is a sensor consisting of a thin flat solid plate, of high thermal conductivity. The front side of the sensor is exposed to the environment, whose Tsa is to be measured, and the backside is thermally insulated. The temperature of the SAT-plate equals Tsa.

In this work we propose introduction of the measured Te in the existing standard (ISO 9869-1). The method for measurement of Tsa, using the SAT, has been demonstrated experimentally for different periods, without solar radiation present and under stable climatic conditions.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Environmental temperature, Sol-air thermometer, Heat transfer coefficient, Thermal transmittance
National Category
Civil Engineering
Identifiers
urn:nbn:se:umu:diva-152736 (URN)10.1016/j.egypro.2017.09.632 (DOI)
Funder
Swedish Energy AgencyThe Kempe Foundations
Available from: 2018-10-21 Created: 2018-10-21 Last updated: 2018-11-09Bibliographically approved
Ohlsson, K. A., Östin, R. & Olofsson, T. (2018). Sol-air thermometer measurement of heat transfer coefficient at building outdoor surface. In: Cold Climate HVAC 2018: Sustainable Buildings in Cold Climates. Paper presented at CONFERENCE on 9th International Cold Climate HVAC 2018, Kiruna, Sweden, March 12-15, 2018 (pp. 329-338). Springer
Open this publication in new window or tab >>Sol-air thermometer measurement of heat transfer coefficient at building outdoor surface
2018 (English)In: Cold Climate HVAC 2018: Sustainable Buildings in Cold Climates, Springer, 2018, p. 329-338Conference paper, Published paper (Refereed)
Abstract [en]

There exists a building energy performance gap between theoretical simulations and the actual energy usage as measured. One potential reason for this gap might be a mismatch between predicted and measured values of the heat flux q through the building envelope. There is therefore a need to develop accurate and more cost-efficient methods for measurement of q. The standard ISO 9869-1 states that, at the outdoor surface, q = ho(Ts − Tenv), where ho is the overall heat transfer coefficient, including both convective and radiative components, Tenv is the environmental temperature, and Ts is the temperature of the building surface. It has previously been shown that the sol-air thermometer (SAT) could be used for convenient measurement of Tenv under dark conditions. In the present work, two SAT units, one heated and the other unheated, were employed for accurate outdoor measurements of ho in cold winter climate. Validation was performed by comparison of results from the new method against measurements, where previously established methodology was used. With current operating conditions, the measurement uncertainty was estimated to be 3.0 and 4.4%, for ho equal to 13 and 29 Wm−2K−1, respectively. The new SAT steady-state method is more cost-effective compared to previous methodology, in that the former involves fewer input quantities (surface emissivity and infrared radiation temperature are unnecessary) to be measured, while giving the same ho results, without any sacrifice in accuracy. SAT methodology thus enables measurement of both Tenv and ho, which characterizes the building thermal environment, and supports estimation of q.

Place, publisher, year, edition, pages
Springer, 2018
Series
Springer Proceedings in Energy
Keywords
Heat transfer coefficient, Sol-air thermometer, Environmental temperature, Building energy performance gap
National Category
Civil Engineering
Identifiers
urn:nbn:se:umu:diva-152725 (URN)10.1007/978-3-030-00662-4_28 (DOI)
Conference
CONFERENCE on 9th International Cold Climate HVAC 2018, Kiruna, Sweden, March 12-15, 2018
Available from: 2018-10-21 Created: 2018-10-21 Last updated: 2019-06-19Bibliographically approved
Ohlsson, K. A., Östin, R. & Olofsson, T. (2018). Step-transient method for measurement of the heat transfer coefficient at surfaces exposed to simulated building outdoor environments using the sol-air thermometer. Journal of Building Physics, 42(3), 373-387
Open this publication in new window or tab >>Step-transient method for measurement of the heat transfer coefficient at surfaces exposed to simulated building outdoor environments using the sol-air thermometer
2018 (English)In: Journal of Building Physics, ISSN 1744-2591, E-ISSN 1744-2583, Vol. 42, no 3, p. 373-387Article in journal (Refereed) Published
Place, publisher, year, edition, pages
Sage Publications, 2018
National Category
Civil Engineering
Identifiers
urn:nbn:se:umu:diva-152733 (URN)10.1177/1744259118764823 (DOI)000450347200009 ()
Available from: 2018-10-21 Created: 2018-10-21 Last updated: 2018-12-19Bibliographically approved
Brembilla, C., Renman, R., Östin, R., Soleimani-Mohseni, M. & Olofsson, T. (2018). The impact of control strategies on space heating system efficiency in low-energy buildings. Building Services Engineering Research & Technology
Open this publication in new window or tab >>The impact of control strategies on space heating system efficiency in low-energy buildings
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2018 (English)In: Building Services Engineering Research & Technology, ISSN 0143-6244, E-ISSN 1477-0849Article in journal (Refereed) Epub ahead of print
Abstract [en]

In this study efficiency factors measures the thermal energy performance for space heating. This study deals with the influence of control strategies on the effriciency factors of space heating and its distribution system. An adaptive control is developed and applied to two types of heating curves (linear and non-linear) for a low-energy building equipped with renewable energy sources. The building is modelled with a hybrid approach (law driven + data driven model). The design of the floor heating is calibrated and validated by assessing the uncertainty bands for low temperatures and mass flow rate. advantages and disavantages of linear and non-linear heating curves are highlighted to illustrate their impact on space heating thermodynamic behaviour and on the efficiency factors of the space heating system.

Practical application: The study reveals that applying commercial building energy simulation software  is worthwhile to determine reliable performance predictions. Oversimplified building models, in particular when considering building thermal mass, are not capable of simulating the thermodynamic response of a building subjected to different control strategies. The application of different heating cuirves (linear and non-linear) to massless building models leaves the amount of mass flow rate delivered to the space heating unchanged when the building is subjected to sharp variations of the outdoor temperature.

Place, publisher, year, edition, pages
London: Sage Publications, 2018
Keywords
Efficiency factors of space heating and distribution system, Calibration through uncertainty bands, Hybrid model of low-energy building: law-driven + data-driven model, Outdoor temperature compensation or heating curve, Feedback and feed-forward control loop + adaptive control, Solar radiation model
National Category
Building Technologies
Identifiers
urn:nbn:se:umu:diva-151980 (URN)10.1177/0143624418822454 (DOI)
Available from: 2018-09-21 Created: 2018-09-21 Last updated: 2019-04-18
Östin, R. (2017). Evaluation of a Single Family Low Energy Building in Cold Climate. Paper presented at 11th Nordic Symposium on Building Physics, NSB2017, 11-14 June 2017, Trondheim, Norway. Energy Procedia, 132, 9-14
Open this publication in new window or tab >>Evaluation of a Single Family Low Energy Building in Cold Climate
2017 (English)In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 132, p. 9-14Article in journal (Refereed) Published
Abstract [en]

Verification of energy performance and indoor climate by detailed field measurements in buildings is of great importance and promotes an assurance in the process of constructing low energy buildings and enables to utilize the full potential of energy efficiency measures.

In the present work a single family building with a heated living space area of 175 m2 has been monitored. The heating system has a wood pellet stove for space heating (SH) and domestic hot water (DHW) and on the roof there are solar collectors in a southerly direction contributing to SH and DHW. SH is distributed by the ventilation system and an under floor heating system which is connected to a heat storage water tank. The incoming outdoor air is pre-heated in an earth-to-air heat exchanger and the building has a measured specific energy usage of 54 kWh/m2year which is far lower than today’s regulation at 130 kWh/m2year in the actual climate zone. The low energy use in the building are due to thick thermal insulation (average Um = 0.18 W/°C m2), an air tight envelope (q50 = 0.165 l/sm2), heat recovery of exhaust air (average 74 % efficiency) and free heat from the ground pre-heating of supply air which is above 2°C even for outdoor temperatures down to -27°C. An essential factor was the low rate of air changes during the heating season about 40 % of the regulated requirement. Measurements of indoor air quality like carbon dioxide occasionally indicated insufficient ventilation.

Place, publisher, year, edition, pages
Elsevier, 2017
Keywords
Energy efficient building, integrated heating system, eart-to-air heat exchanger, indoor air carbon dioxide
National Category
Energy Engineering
Identifiers
urn:nbn:se:umu:diva-140771 (URN)10.1016/j.egypro.2017.09.623 (DOI)000426435500002 ()
Conference
11th Nordic Symposium on Building Physics, NSB2017, 11-14 June 2017, Trondheim, Norway
Note

Special issue: 11th Nordic Symposium on Building Physics, NSB2017, 11-14 June 2017, Trondheim, Norway

Available from: 2017-10-19 Created: 2017-10-19 Last updated: 2018-06-25Bibliographically approved
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