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Rönnelid, Mats
Publications (4 of 4) Show all publications
Gustafsson, M., Karlsson, B. & Rönnelid, M. (2017). How the electric meter configuration affect the monitored amount of self-consumed and produced excess electricity from PV systems: case study in Sweden. Energy and Buildings, 138, 60-68
Open this publication in new window or tab >>How the electric meter configuration affect the monitored amount of self-consumed and produced excess electricity from PV systems: case study in Sweden
2017 (English)In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 138, p. 60-68Article in journal (Refereed) Published
Abstract [en]

This study evaluates how the principal function of bi-directional electric meters affects the monitored amount of self-consumed and produced excess electricity for dwelling buildings connected to the grid by three phases. The electric meters momentarily record the sum of the phases or the phases individually and then summarize the recorded values to a suitable time period and is then collected by the grid owner. In Sweden, both electric meter configurations fulfill laws and regulations.

The meter configuration affects the monitored distribution of self-consumed and produced excess electricity significantly for the investigated single-family house but is negligible for the investigated multi-dwelling buildings. The monitored self-consumed electricity produced by the PV installation for the single-family house varies between 24% and 55% depending on the configuration and how the inverter is installed for the investigated year. The difference in economic value for the produced electricity varies between 79.3 to 142 Euros.

Due to the electric meter configuration, the profitability of PV systems will be different for identical single-family houses with identical conditions. This should be corrected for a well-functioning market. It is also important to decide how the configuration should be designed to ensure that different incentives and enablers results in desired effects.

Keywords
Solar PV technology; Buildings and PV systems; Electric meter configuration; Energy market; Energy policy
National Category
Energy Engineering
Research subject
Energy, Forests and Built Environments, Reesbe företagsforskarskola
Identifiers
urn:nbn:se:du-23554 (URN)10.1016/j.enbuild.2016.11.010 (DOI)000394061200006 ()
Funder
Knowledge Foundation
Available from: 2016-12-12 Created: 2016-12-12 Last updated: 2017-11-29Bibliographically approved
Joudi, A., Cehlin, M., Svedung, H., Rönnelid, M. & Moshfegh, B. (2017). Numerical and experimental investigation of the influence of infrared reflective interior surfaces on building temperature distributions. Indoor + Built Environment, 26(3), 355-367
Open this publication in new window or tab >>Numerical and experimental investigation of the influence of infrared reflective interior surfaces on building temperature distributions
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2017 (English)In: Indoor + Built Environment, ISSN 1420-326X, E-ISSN 1423-0070, Vol. 26, no 3, p. 355-367Article in journal (Refereed) Published
Abstract [en]

Radiative properties of interior surfaces can affect not only the building heat flux but also the indoor environment, the latter of which has not been thoroughly investigated. The aim of this study is to analyse the effect of surface emissivity on indoor air and surface temperature distributions in a test cabin with reflective interior surfaces. This was done by comparing experimental and simulation data of the test cabin with that of a normal cabin. This study employs transient computational fluid dynamics (CFD) using re-normalisation group (RNG) k–" model, surface-to-surface radiation model and an enhanced wall function. Boundary conditions were assigned to exterior surfaces under variable outdoor conditions. The numerical and the measurement results indicate that using interior reflective surfaces will affect the indoor air temperature distribution by increasing the vertical temperature gradient depending on the time of the day. CFD simulations with high spatial resolution results show increased interior surface temperature gradients consistent with the increased vertical air temperature gradient. The influence of reflective surfaces is potentially greater with higher indoor surface temperature asymmetry. The vertical indoor air temperature gradient and surface temperatures are important parameters for indoor thermal comfort.

Keywords
reflective interior surfaces, indoor air temperature gradient, transient computational fluid dynamics, surface-to-surface radiation, building thermal performance
National Category
Civil Engineering
Research subject
Energy, Forests and Built Environments
Identifiers
urn:nbn:se:du-21040 (URN)10.1177/1420326X15609966 (DOI)000399487300007 ()
Available from: 2016-02-15 Created: 2016-02-15 Last updated: 2017-05-05Bibliographically approved
Gustafsson, M., Rönnelid, M., Trygg, L. & Karlsson, B. (2016). CO2 emission evaluation of energy conserving measures in buildings connected to a district heating system: Case study of a multi-dwelling building in Sweden. Energy, 111, 341-350
Open this publication in new window or tab >>CO2 emission evaluation of energy conserving measures in buildings connected to a district heating system: Case study of a multi-dwelling building in Sweden
2016 (English)In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 111, p. 341-350Article in journal (Refereed) Published
Abstract [en]

When taking action to fulfill the directives from the European Union, energy conserving measures will be implemented in the building sector. If buildings are connected to district heating systems, a reduced heat demand will influence the electricity production if the reduced heat demand is covered by combined heat and power plants.This study analyze five different energy conserving measures in a multi-dwelling building regarding how they affect the marginal production units in the district heating system in Gävle, Sweden. For CO2 emission evaluations, two different combinations of heat and electricity conserving measures are compared to an installation of an exhaust air heat pump.The different energy conserving measures affect the district heating system in different ways. The results show that installing an exhaust air heat pump affects the use/production of electricity in the district heating system most and electricity conserving measures result in reduced use of electricity in the building, reduced use of electricity for production of heat in the district heating system and an increase of electricity production.The conclusion is that electricity use in the building is the most important factor to consider when energy conserving measures are introduced in buildings within the district heating system in Gävle.

Keywords
District heating system; Energy efficiency; Greenhouse gases; Refurbishment; Simulation
National Category
Energy Engineering
Research subject
Energy, Forests and Built Environments
Identifiers
urn:nbn:se:du-21779 (URN)10.1016/j.energy.2016.05.002 (DOI)000384776900029 ()2-s2.0-84973177469 (Scopus ID)
Available from: 2016-06-20 Created: 2016-06-20 Last updated: 2017-11-28Bibliographically approved
Trygg, L., Björk, C., Karlsson, P., Rönnelid, M. & Djuric Ilic, D. (2016). Heat collaboration for increased resource efficiency: A case study of a regional district heating system and a mine. In: : . Paper presented at The 15th International Symposium on District Heating and Cooling, September 4-7, 2016, Seoul, Republic of Korea (South Korea).
Open this publication in new window or tab >>Heat collaboration for increased resource efficiency: A case study of a regional district heating system and a mine
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2016 (English)Conference paper, Published paper (Other academic)
Abstract [en]

To rapidly develop sustainable energy systems is crucial for the whole society's transition towards sustainability. System efficiency and reduced climate impact are important parts of this. Swedish district heating systems are fairly well developed, mainly based on non-fossil fuels, and includes energy-efficient technologies (such as combined heat and power production and fuel gas condensation). Increased use of district heating is therefore considered as a way to increase energy-efficiency, to phase out fossil energy for heating purposes, and subsequently to a reduction of global CO2 emissions. 

The aim of this paper is to study system impact of increased demand of district heating by analysing a collaboration on heat supply between the local energy supplier of Ludvika in Sweden and a nearby mine. The paper analyses economic potential, as well as the potential for more efficient operation of district heating production plants in the local district heating system. The heat demand in the mine is presently supplied from a small-scale biomass-fuelled heat-only boiler located near to the mine. The system consists of two biomass-fuelled heat-only boilers with fuel gas condensers. The consequences of connecting the heat demand of the mine with the municipal district heating system is analyzed using the cost optimization model MODEST. 

Keywords
District heating, mine, collaboration, system perspective
National Category
Energy Engineering
Research subject
Energy, Forests and Built Environments
Identifiers
urn:nbn:se:du-23360 (URN)
Conference
The 15th International Symposium on District Heating and Cooling, September 4-7, 2016, Seoul, Republic of Korea (South Korea)
Projects
Testbädd gruvor
Funder
VINNOVA
Available from: 2016-11-15 Created: 2016-11-15 Last updated: 2017-02-23Bibliographically approved
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