No abstract

The focus of this research paper is to develop a verified simulation model for a cooling panel with integrated phase-change materials (PCMs)—a stainless steel panel filled with PCM and integrated hydronic piping circuit. This solution is targeted for passive cooling of residential buildings in Baltic Sea region that experience overheating for most of the year due to highly insulated building envelopes and extensive glazing—a phenomena for nearly zero energy buildings (NZEBs). This approach aims to maintain comfortable indoor temperature all year round by passive means—free-cooling, adiabatic (evaporative) cooling or limited mechanical cooling. The simulations are performed with IDA ICE 4.8 and the measurements for simulation model verification are collected from a test chamber. The results show that reasonable agreement can be reached for simulated and experimentally measured data.

No abstract

Nowadays national and international directives have focused on improving energy efficiency in the building sector. According to them, energy consumption and emissions of buildings must be reduced. This can be achieved by balancing energy demand in buildings. In this context, this paper proposes a buildings’ energy demand balancing method using the building energy consumption simulation program IDA ICE and real measurements. A 3D model of the building was developed, energy consumption and indoor climate of the building was monitored throughout the year, the behaviour of the occupants (a survey was conducted) was analysed, dynamic change of the weather was studied and all data were integrated into IDA ICE simulation. In order to increase the energy efficiency of buildings, the possibilities of optimization of heat production equipment and heating devices, as well as inspecting and optimization of ventilation and cooling equipment were considered. By adjusting the parameters of the heating system of the researched object, the energy consumption of the auto centre decreased to 39.3 kWh/m2 per year. One of the most popular methods of balancing energy demand in recent years – the creation of smart grids – is also considered.

As building codes are pushing towards higher energy efficiency and the arrival of nearly Zero Energy Building (nZEB) requirements for all new buildings are just around the corner the need for alternative, high efficiency heating and cooling solutions for nZEB’s is greater than ever. Also as experience with renewable energy sources has proven the energy demand and energy generation rarely overlaps and it does not allow to fully utilise some renewable energy sources. This is a simulation study that focuses on integrated cooling and energy storage system utilising phase-change materials (PCM). Several types of thermally activated slabs with different PCM thicknesses were simulated in order to find the most optimal PCM thickness with melting point temperature that can support passive cooling methods based on adiabatic cooling principles. Two calculation tools were used for the study – IDA ICE 4.8 and U-NORM 2012-2 to calculate the properties of the slabs and potential of application in well insulated residential building in Baltic climate. The results showed that the optimal thickness for thermally activated PCM layer (large flat containers) range from 25 mm to 90 mm, and for layers with no thermal activation – 180 mm and more. Moreover the results show that apart from energy storage the thermally activated panel can increase thermal comfort conditions.

This Thesis focuses on the development of an experimentally validated equation based simulation model of a cooling panel with integrated latent thermal storage system for utilization in Nearly Zero-Energy Buildings (NZEB) buildings. Development of such model is necessary in order for this technology to achieve industry-readiness. The Thesis is composed of a literature review and an experimental study. The literature review focuses on NZEB requirements in the European Union (EU) member countries, previous research in the field of passive cooling technologies and latent thermal storage systems. The passive cooling technologies described in the literature review are considered potential cooling energy sources to be coupled with the researched cooling panel. A combination of these technologies may be used to address overheating issues in NZEB buildings. The experimental study is focused on the development and validation of the aforementioned cooling panel simulation model. The numerical model is developed by using dynamic simulation software IDA ICE and is composed of sub-models written in Neutral Model Format (NMF). The simulation model is validated against experimental measurements carried out in a test chamber that was developed specially for this study. Moreover, a comparative study is carried out where the results generated by the developed and validated simulation model are compared against a previous CFD simulation study results acquired by a different research team. The accuracy of the results generated by the simulation model when compared with experimental measurements is a maximum deviation of 2.2 °C and a root mean square error of 1.01 °C. The results indicate that the accuracy reached by the simulation model is equal or higher than reported in other similar studies, therefore the accuracy is considered suitable for energy, thermal comfort and cooling load simulation in whole building scale simulation studies. The experimental study also provides several limitations for the proposed simulation model that shall be respected in order to reach the accuracy claimed in this study.

Promocijas darba mērķis – uz vienādojumiem balstīta simulācijas modeļa izstrāde dzēšanas panelim ar integrētu latento termālās enerģijas akumulatoru, kas ir eksperimentāli validēts un paredzēts izmatošanai gandrīz nulles enerģijas ēkās. Šāda modeļa izstrāde ir nepieciešama, lai šī tehnoloģija būtu gatava izmantošanai būvniecības industrijā. Promocijas darbs ietver literatūras apskatu un eksperimentālu pētījumu. Literatūras apskatā ir iekļauts pārskats par gandrīz nulles enerģijas ēku prasībām Eiropas Savienības dalībvalstīs, iepriekšējiem pētījumiem pasīvās dzesēšanas tehnoloģiju jomā un latento termālās enerģijas akumulatoru tehnoloģijām. Pasīvās dzesēšanas sistēmas, kas ir aplūkotas literatūras apskatā, tiek uzskatītas par potenciāliem dzesēšanas enerģijas avotiem, ko var izmantot kopā ar iepriekš minētajiem dzesēšanas paneļiem. Šo tehnoloģiju kombināciju var lietot, lai reaģētu uz telpu pārkaršanas problēmām gandrīz nulles enerģijas ēkās. Eksperimentālā pētījuma mērķis ir iepriekš minētā paneļa simulācijas modeļa izstrāde un validācija. Pētījumā izmantotais matemātiskais modelis ir izstrādāts, izmantojot dinamisko simulāciju rīku IDA ICE, un ietver apakšmodeļus, kas rakstīti NMF (Neutral Model Format) programmēšanas valodā. Simulāciju modelis ir validēts eksperimentālos mērījumos, kas veikti testa kamerā, kas izstrādāta speciāli šim pētījumam. Eksperimentālajā pētījumā veikta arī salīdzinoša analīze, kurā savstarpēji salīdzināti izstrādātā simulācijas modeļa rezultāti ar rezultātiem, kas iegūti no plūsmas dinamikas simulācijas (CFD), ko iepriekš izstrādājusi cita pētnieku komanda. Izstrādātā simulācijas modeļa precizitāte attiecībā pret eksperimentālajiem mērījumiem testa kamerā: maksimālā novirze ir 2,2 °C, vidējā kvadrātiskā kļūda – 1,01 °C. Rezultāti liecina par to, ka izstrādātā modeļa precizitāte ir līdzvērtīga vai augstāka par precizitāti, kas ziņota citos līdzīgos pētījumos. Līdz ar to var uzskatīt, ka šī modeļa precizitāte ir pietiekama, lai to izmantotu enerģijas patēriņa, termālā komforta un dzesēšanas slodžu simulācijās, kas ietver pilnu ēkas apjomu. Eksperimentālajā pētījumā ir norādīti arī vairāki izstrādātā modeļa ierobežojumi, kas būtu jāņem vērā, lai sasniegtu precizitāti, kas uzrādīta šajā pētījumā.

No abstract