Danish, Estonian and Finnish NZEB requirements comparison with European Commission recommendations for office buildings in Nordic and Oceanic climates

Direct comparison of building energy performance levels between countries is usually not possible due to differences in climatic conditions, calculation methods, primary energy (PE) factors and input data. The aim of this paper is to analyse the differences in nearly zero energy office buildings requirements and energy calculation methodology in Denmark, Finland, and Estonia. The study is based on a newly built Estonian office building, designed to meet national NZEB requirements. To account for the climatic differences between the countries a heating-degree-days-based correction factor was applied for building envelope thermal transmittance. NZEB requirements for each country are compared with European Commission (EC) recommended values (EU 2016/1318) using normalization and benchmarking through detailed computer simulations. National NZEB primary energy threshold was needed to be reduced by 7% in Denmark and by 23% in Estonia to meet EC recommendations. At the same time, the flagship reference building, that was better than Estonian NZEB, met both Nordic and Oceanic EC recommendations. Finnish NZEB requirement was not exceeded with any building configuration applied in this study, indicating that Finnish NZEB is considerably less strict compared to Danish and Estonian ones

Compliance with Summer Thermal Comfort Requirements in Apartment Buildings

In this study we have investigated the compliance with summer thermal comfort requirements of 16 new apartment buildings in Estonia by modelling and simulating dwellings using energy and indoor climate simulation software IDA-ICE. We also conducted field measurements of indoor temperature in 17 dwellings in 16 different apartment buildings during the period from 1 July to 31 August 2014. It has been found that 81.3% of the simulated buildings do not comply with the requirements. Measurements show that overheating can be a problem in apartment buildings also in cold climate regions

Ilmanvaihto- ja jäähdytysjärjestelmien resilienssi lämpöaaltojen ja hengitystieinfektioiden suhteen : Uudis- ja korjausrakennusten teknisten ratkaisujen toiminta muuttuvissa olosuhteissa

Tutkimuksessa tehtiin laskennallisia tarkasteluja helleaaltojen vaikutuksista sisälämpötilaan sekä kenttämittauksia ja virtaussimulointeja ilmanvaihdon mitoituksen merkityksestä hengitystieinfektioiden torjunnassa. Lisäksi arvioitiin korkeiden lämpötilojen terveyshaittoja sekä influenssaviruksen terveysvaikutuksien ja koronapandemian merkitystä Suomen ylikuolleisuuteen. Passiivisilla auringonsuojaratkaisuilla ja ilmanvaihdon tehostuksella voidaan vähentää rakennusten ylilämpenemistä, mutta ne eivät yksistään riitä torjumaan sitä. Helleaalloista aiheutuu Suomessa vuosittain keskimäärin noin 110 ennenaikaista kuolemaa ja 170 sairaalahoitojaksoa, ja tulevaisuudessa haitat voivat moninkertaistua. Asuntojen ylilämpenemisen torjuntatoimien avulla on mahdollista ehkäistä merkittävä osuus vakavista terveyshaitoista. Nykyiset ilmavirrat ovat opetustiloissa ja kuntosalissa riittäviä hengitysinfektioriskin hallintaan. Avotoimistossa noin 20 %:a pienempi henkilömäärä voidaan nähdä järkevänä ratkaisuna epidemiatilanteessa. Hengitystieinfektiot ovat yleisin lyhyiden työstä poissaolojen syy Suomessa ja ne aiheuttavat sekä työnantajille että yhteiskunnalle kustannuksia sairauspoissaoloina, lisääntyneinä terveydenhuollon menoina ja suurentuneena kuolleisuutena.Tämä julkaisu on toteutettu osana valtioneuvoston selvitys- ja tutkimussuunnitelman toimeenpanoa. (tietokayttoon.fi) Julkaisun sisällöstä vastaavat tiedon tuottajat, eikä tekstisisältö välttämättä edusta valtioneuvoston näkemystä

Overheating Prevention and Daylighting in Buildings without Mechanical Cooling. clekuumenemise v\ue4ltimine ja loomuliku valguse tagamine mehaanilise jahutuseta hoonetes

Doctoral thesis 54/2019 Doktorit\uf6\uf6 54/201

Sensitivity of a Lumped-Capacitance Building Thermal Modelling Approach for Energy-Market-Scale Flexibility Studies

Despite all the literature on building energy management, building-stock-scale models depicting its impact for energy-market-scale optimisation models are lacking. To address this shortcoming, an open-source tool called ArchetypeBuildingModel.jl has been developed for aggregating building-stock-level data into simplified lumped-capacitance thermal models compatible with existing open-source energy-system modelling frameworks. This paper aims to demonstrate the feasibility of these simplified thermal models by comparing their performance against dedicated building simulation software, as well as examining their sensitivity to key modelling and parameter assumptions. Modelling and parameter assumptions comparable to the existing literature achieved an acceptable performance according to ASHRAE Guideline 14 across all tested buildings and nodal configurations. The most robust performance was achieved with a period of variations above 13 days and interior node depth between 0.1 and 0.2 for structural thermal mass calibrations, and with external shading coefficients between 0.6 and 1.0 and solar heat gain convective fractions between 0.4 and 0.6 for solar heat gain calibrations. Furthermore, three-plus-node lumped-capacitance thermal models are recommended when modelling buildings with structures varying in terms of thermal mass. Nevertheless, the ArchetypeBuildingModel.jl performance was found to be robust against uncertain key parameter assumptions, making it plausible for energy-market-scale applications

The Effect of Hydronic Balancing on Room Temperature and Heat Pump Efficiency of a Building with Underfloor Heating

Underfloor heating is a common solution in single-family houses and a suitable solution for nearly zero-energy buildings as a low temperature heating system. According to general practice, the underfloor heating systems should be balanced to assure stable room temperatures and avoid under heating in rooms with higher heat losses. The purpose of the presented study was to analyze the effect of hydronic balancing on the room temperature fluctuations and heat pump performance. The tests were performed at full-scale nearly zero-energy building test facility with under floor heating and an air-to-water heat pump. We measured room and floor temperatures and monitored the heat pump electricity use and heat output. The heat balance of rooms was disturbed with internal gains introduced to several rooms in cycles. The results showed that room temperature fluctuations slightly increased of an unbalanced system, however during all tests, the average temperature fluctuations during night time were below 0.2 °C, so both systems performed well. We identified a negative effect of balancing on the heat pump performance as higher COP was measured in case of an unbalanced system. The results allow to conclude that in the case of studied system with one manifold and relatively small loop length differences the balancing had negligible effect on system performance. However, the topic should be studied further in more unfavorable conditions.Peer reviewe

Heating Sizing Power Reduction in Buildings Connected to District Heating with Dynamically Controlled DHW Setback and Flow Limiters

| openaire: EC/H2020/856602/EU//FINEST TWINSSpace Heating (SH) substations in District Heating-based (DH) systems are typically dimensioned at the design outdoor temperature without accounting for internal and solar heat gains. In residential buildings, the total required DH power typically also includes the need for Domestic Hot Water (DHW). This practice results in oversized substations and high DH design flow rates, which, due to heat gains and building thermal mass utilization in building operation, rarely, if ever, occur. Modern buildings maintain the desired indoor temperature with lower heating power by controlling the SH supply temperature with an outdoor-air-dependent heating curve and heating water flow with room unit thermostats. Applying a dynamic heating control algorithm can be considered one option to reduce the required DH power and optimize the DH network. Another possibility to decrease the needed power is controlling the DH flow by prioritizing DHW production and limiting the DH flow for SH. This study proposed a novel sizing method for the DH substation that quantifies the effects of dynamic control and flow limiters. Building models with detailed hydronic plants, accounting for internal heat gains, and using conventional and dynamic heating controls were developed in the IDA Indoor Climate and Energy simulation tool. The results show a potential DH side power reduction of up to 25%.Peer reviewe

A comparative study on cooling period thermal comfort assessment in modern open office landscape in Estonia

| openaire: EC/H2020/856602/EU//FINEST TWINSLocal thermal comfort and draught rate has been studied widely. There has been more meaningful research performed in controlled boundary condition situations than in actual work environments involving occupants. Thermal comfort conditions in office buildings in Estonia have been barely investigated in the past. In this paper, the results of thermal comfort and draught rate assessment in five office buildings in Tallinn are presented and discussed. Studied office landscapes vary in heating, ventilation and cooling system parameters, room units, and elements. All sample buildings were less than six years old, equipped with dedicated outdoor air ventilation system and room conditioning units. The on-site measurements consisted of thermal comfort and draught rate assessment with indoor climate questionnaire. The purpose of the survey is to assess the correspondence between heating, ventilation and cooling system design, and the actual situation. Results show, whether and in what extent the standard-based criteriafor thermal comfort is suitable for actual usage of the occupants. Preferring one room conditioning unit type or system may not guarantee better thermal environment without draught. Although some heating, ventilation and cooling systems observed in this study should create the prerequisites for ensuring more comfort, results show that this is not the case for all buildings in this study.Peer reviewe