| 1. |
- Berggren, Björn, et al.
(författare)
-
Köldbryggor : Hur har kunskapen utvecklats i Sverige
- 2022
-
Ingår i: Bygg & teknik. - 0281-658X. ; :2, s. 42-45
-
Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Byggnaders energibehov behöver minska i kombination med att energiförsörjningen (el, värme, gas, med mera) behöver fasa ut användandet av fossila bränslen för att motverka den pågående klimatförändringen. Olika strategier kan tillämpas för att utforma och bygga/renovera energieffektiva byggnader. En viktig åtgärd, oavsett strategi, är att minska energibehovet, vilket i Sverige vanligtvis innefattar ett tätt och välisolerat klimatskal i kombination med mekanisk ventilation, med värmeåtervinning. Den huvudsakliga orsaken till byggnadens värmebehov i denna typ av byggnader är relaterat till transmissionsförluster genom klimatskalet, där köldbryggorna kan stå för mer än 30 procent av transmissionsförlusterna. Bristande beräkningar och/eller uppskattningar av köldbryggor kan leda till stora konsekvenser. Dels för brukare, dels för konsulter och entreprenörer.
|
|
| 2. |
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
- Simanic, Branko
(författare)
-
Energy Auditing and Efficiency in a Chain Hotel : the Case of Scandic, Järva Krog
- 2011
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Energy efficiency and conservation measures in hotels is an area of research at the Department of Energy Technology, Royal Institute of Technology in Stockholm (KTH), Sweden. As a continuation of the research work, this project was focused on a hotel's resource-use performance, considering both internal and external factors that influence their consumption. The work comprised a literature study on energy efficiency and conservation measures in the built environment, focusing on hotel buildings, as well as an analysis of existing building assessment tools. An auditing and monitoring process was applied at one Scandic hotel, Järva Krog, which was selected with the support of Scandic management. Another four Scandic hotels were included in this study, using their data on energy/water consumption for the past five years. The tourism industry is one of the world’s largest single industries, experiencing rapid expansion in recent decades. The number of international tourist arrivals increased from 441 million in 1990 to 763 million in 2004 (WTO, 2005). The hotel industry forms the largest part of the tourism industry with more than 300 000 hotels worldwide. Hotels offer their lodging capacities with the highest possible comfort and quality, without compromise. High demands on comfort and the level of services offered require an intensive utilization of energy and water. The price of energy has been increasing continuously during the last few years, with electricity increasing 6 % on an annual basis, which has made energy expenses increase rapidly during the past years. Adding high energy costs to concerns about CO2 emissions, highlights the importance of accurate information for energy management within any hotel facility. A need to decrease energy expenditure demands depending of knowledge relating to hotel facility consumption. The objective of this thesis is to understand energy performance and energy distribution within one typical chain hotel facility, and how this understanding can be applied to a selected group of similar hotels as well as to define the relationship between the factors behind energy expenditure. Such factors include outdoor climate as an external quantitative factor; HVAC system efficiency, lighting, occupancy rate and number of food covers sold as internal quantitative factors; and personnel behavior, operation/maintenance routines/levels as internal qualitative factors.
|
|
| 7. |
- Simanic, Branko
(författare)
-
Energy use in hotels and low-energy schools : Measurements and analysis of energy use and user-related parameters
- 2020
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Decreasing CO2 emissions in the building sector by improving energy efficiency isan essential part of the goal to reduce global CO2 emissions, as the sector accountedfor nearly 40 percent of the energy-related CO2 emissions in 2017.There are six main parameters that affect a building's energy use. These areoutdoor climate, building envelope properties, building services and energysystems, operation and maintenance, user-related activities and indoor climate. Thefirst three parameters can be classified as technical parameters and these have beenvery well studied in the past. To further improve a building's energy efficiency, morestudies should be carried out with regard to the last three parameters, which havenot been studied as extensively as the technical parameters. These parameters canbe classified as user-related parameters.The overall aim of this thesis is to contribute to achieving global climate goalsby improving the energy efficiency of buildings. This has been done by studyingboth calculated and measured energy use in order to understand which of theparameters have major impacts on energy use and should therefore be taken intoconsideration.This thesis studies calculated and measured energy use in two types of buildings.It focuses mainly on how user-related parameters affected energy use in five hotels,located in Stockholm and all belonging to the same hotel chain, and seven newlybuilt low-energy schools located in the southern part of Sweden. Data from thehotels was collected over several years and included measurements of energy useand the influence of two user-related parameters. In the schools, data frommeasurements regarding energy use, indoor air temperature, indoor CO2concentration, and several user-related parameters were collected over a one-yearperiod. Descriptive statistics and simulations of the buildings' energy uses were usedto analyse the collected data.The hotels in the study showed large differences in total energy use. It was alsoshown that results from one hotel, with respect to the studied parameters thataffected measured energy use, could not be applied to the other, similar, hotels. Oneway of attaining more detailed information and identifying the energy deviationswould be to study a hotel’s sub-systems (for space heating/cooling, pool, etc)individually. This would help engineers in their design work and allow more8accurate calculations of potential energy savings of any capital investments in thespace heating systems, or any other systems.Comparisons between measured and estimated energy use showed that there werelarge discrepancies in the studied schools. These varied from -44 to +28 percent.The study showed that the user-related parameters had a more dominant influenceon the variations of building energy use than the technical parameters. Of the studiedparameters, indoor air temperatures, ventilation rates and ventilation operating timeswere shown to be the user-related parameters having the greatest influence onbuilding energy use. The use of electricity for lighting and electrical appliances hadsomewhat less influence on the total energy use while occupancy rates and energyuse for domestic hot water supplies had little influence in the studied schools.Although only seven low-energy schools were included in the study, it could be seenthat the measured user-related parameters could vary considerably. This means thatnot only more measurements in more schools are needed in the future but also thatby only presenting an average value per parameter energy engineers could be misledwhen calculating energy use. For thisreason, this study also presents standarddeviations of the studied parameters.
|
|
| 8. |
- Simanic, Branko, et al.
(författare)
-
Indoor air temperatures, CO2 concentrations and ventilation rates : Long-term measurements in newly built low-energy schools in Sweden
- 2019
-
Ingår i: Journal of Building Engineering. - : Elsevier BV. - 2352-7102. ; 25
-
Tidskriftsartikel (refereegranskat)abstract
- Within a period of ten years a large number of schools need to be built in Sweden and these new schools need to be nearly zero energy buildings. School classrooms are required to provide healthy learning environments to help children perceive and process information. This means that classrooms must provide adequate levels of indoor air quality and thermal comfort. This article investigates CO2 concentration levels and indoor air temperatures in several recently built, low-energy schools in Sweden, and compares them with design criteria stipulated in specific international standards and Swedish regulations to provide feedback to the building construction industry. Field measurements of CO2 concentrations, indoor air temperatures and ventilation rates in seven low-energy schools, with a total of 145 classrooms, taken during several months spanning both summer and winter periods, are analysed in this article. All the schools in the study have mechanical supply and exhaust ventilation systems with demand control devices in the classrooms. The study shows that all the classrooms, in general, comply with the design criteria regarding indoor air temperatures and CO2 concentrations in EN15251, ASHRAE 62.1 and the Swedish national regulations and recommendations. Median values of indoor air temperatures were between 19 and 23.5 °C in all classrooms during school hours. The 90-percentile levels of CO2 concentrations were below 1000 ppm in 60 of 61 classrooms in which these measurements could take place. It is concluded that during this long-term measurements in the studied seven low-energy schools, modern HVAC systems with demand control and heat recovery, in general, provided satisfactory indoor climates in terms of CO2 levels and indoor air temperatures.
|
|
| 9. |
- Simanic, Branko, et al.
(författare)
-
Influence of user-related parameters on calculated energy use in low-energy school buildings
- 2020
-
Ingår i: Energies. - : MDPI AG. - 1996-1073. ; 13:11
-
Tidskriftsartikel (refereegranskat)abstract
- Literature and experience show that there are large discrepancies between the calculated and measured building energy usages, where user-related parameters are significant factors with regard to energy use in low-energy buildings. Furthermore, the difficulties encountered when quantifying these parameters compound these discrepancies. The main aim of this study was to provide feedback that would help the building industry and research communities to predict more accurately the impact of the user-related parameters on energy performance. The results of the study would, subsequently, contribute to minimizing the discrepancies between calculated and measured energy use. This article analyses simulated building energy use based on randomly chosen combinations of measured user-related parameters in three recently built low-energy schools in Sweden. The results show that energy performance can span from 30 to 160 kWh/(m2 y) simply by varying the combination of previously measured user-related parameters in building energy simulations. The study shows that the set points for indoor air temperatures during the heating season and the energy required to run a demand-controlled ventilation system have an extensive influence, while tenant electricity use has a slightly lower influence on building energy use. Variations in occupancy rates and energy for hot water usage have the smallest influences on building energy use.
|
|
| 10. |
- Simanic, Branko, et al.
(författare)
-
Predicted and measured user-related energy usage in newly built low-energy schools in Sweden
- 2020
-
Ingår i: Journal of Building Engineering. - : Elsevier BV. - 2352-7102. ; 29
-
Tidskriftsartikel (refereegranskat)abstract
- Literature and experience show that the differences between calculated and measured building energy performance still exist. The literature shows that user-related parameters are significant with regard to energy performance in low-energy buildings and this means that the choice of parameters is one of the main factors leading to this difference. However, the parameters themselves are associated with uncertainty when predicting and calculating their effects. One of the identified research gaps is the lack of data on behavioral energy use and profiles. The aim of this study is to provide relevant feedback, which will help the building industry and research communities to predict more accurately the user-related impacts on energy performance and, subsequently, enable reduction of the differences between calculated and measured energy performance. This article analyses measured user-related parameters and building energy usage in seven recently built low-energy schools in Sweden. Regression analysis is applied when analysing the parameters and their influence on energy usage. With the help of the measurements carried out, all the studied schools were determined to be low-energy schools. The results show differences between calculated and measured building energy performances in the studied schools and these vary from –44 to +28%. At least 33% of measured energy usage depends on the user-related parameters. Ventilation rates and running times as well as space heating set points were found to be the user-related parameters that have the most significant effects on total energy usage. Finally, some important recommendations for good building operation practice and measurement methodology are presented.
|
|
