Assessment Of Walls with Phase Change Materials Through Synergistic and Performance Measures Using Experimental and Simulated Test Houses

Current research on living and working spaces continues to strive to identify the most energy-efficient methods for heating and cooling, and many novel technologies have emerged from the research. One of the most promising, and the topic of this quantitative analysis, is the retrofitting of phase change materials (PCMs) into the walls of structures. Research has shown positive results, such as a reduced transfer of heat through walls, when PCMs are retrofitted into wall construction. The present research takes previously gathered data from test houses, built with typical North American framing, and simulates an additional fourteen test houses from the gathered data. The simulated houses consisted of a unique combination of walls retrofitted with and without PCM in them. The fourteen unique simulations allowed for seven metrics, such as max heat flux, time delays (start, peak, and end), total heat, heat flux average, and standard deviation, to be measured. Most of the measure indicated a positive correlation with the addition of PCM being retrofitted into a wall. From the results, the east, west and south walls emerged to be the most influential when it came to the seven measures, and it is recommended that at least one of these three walls be included when retrofitting building

Numerical simulation of phase change material composite wallboard in a multi-layered building envelope.

Residential buildings account for a large portion of total energy consumption in the United States. Residential energy usage can be dramatically reduced by improving the efficiency of building envelope systems. One such method is to incorporate thermally massive construction materials into the building envelope. This benefits building operation by reducing the energy requirement for maintaining thermal comfort, downsizing the AC/heating equipment, and shifting the time of the peak load on the electrical grid. Phase change materials (PCMs) are promising material for that purpose. When impregnated or encapsulated into wallboard or concrete systems, PCMs can greatly enhance their thermal energy storage capacity and effective thermal mass. In this work, a numerical study is conducted to investigate the characteristics of PCMs in building applications. For that purpose a one-dimensional, transient heat equation for a multilayered building envelope is solved using the Crank-Nicolson scheme. The effect of PCM is modeled with a latent heat source term. The code also incorporates sun loading and uses real weather data. Using this code a PCM composite wallboard incorporated into the walls and roof of a residential building was examined. The PCM performance was studied under all seasonal conditions using TMY3 data for exterior boundary conditions. Comparisons were made between different PCM wallboard locations. This work shows that there is an optimized location for PCM placement within building envelope and the location depends on the thermal resistance of the layers between the PCM and the exterior boundary. The energy savings potential was identified by comparing the performance of the PCM wallboard with the performance of a building envelope without PCM. This work shows that a PCM composite wallboard enhanced building can reduce the annual cooling load from the walls by as much as 19.7% and from the roof by as much as 8.1%. Similarly, the annual heating loads can be reduced by as much as 6% and 6.4% for the walls and roof respectively. It was also shown that the peak electricity load can be shifted by as much as three hours in the summer for a south facing wall. Studies are also conducted to compare the PCM performance across three climate zones. This work shows that PCM performance varies significantly across these zones

High-Performance Integrated Window and Façade Solutions for California

The researchers developed a new generation of high-performance façade systems and supporting design and management tools to support industry in meeting California’s greenhouse gas reduction targets, reduce energy consumption, and enable an adaptable response to minimize real-time demands on the electricity grid. The project resulted in five outcomes: (1) The research team developed an R-5, 1-inch thick, triplepane, insulating glass unit with a novel low-conductance aluminum frame. This technology can help significantly reduce residential cooling and heating loads, particularly during the evening. (2) The team developed a prototype of a windowintegrated local ventilation and energy recovery device that provides clean, dry fresh air through the façade with minimal energy requirements. (3) A daylight-redirecting louver system was prototyped to redirect sunlight 15–40 feet from the window. Simulations estimated that lighting energy use could be reduced by 35–54 percent without glare. (4) A control system incorporating physics-based equations and a mathematical solver was prototyped and field tested to demonstrate feasibility. Simulations estimated that total electricity costs could be reduced by 9-28 percent on sunny summer days through adaptive control of operable shading and daylighting components and the thermostat compared to state-of-the-art automatic façade controls in commercial building perimeter zones. (5) Supporting models and tools needed by industry for technology R&D and market transformation activities were validated. Attaining California’s clean energy goals require making a fundamental shift from today’s ad-hoc assemblages of static components to turnkey, intelligent, responsive, integrated building façade systems. These systems offered significant reductions in energy use, peak demand, and operating cost in California

Architectural and Management Strategies for the Design, Construction and Operation of Energy Efficient and Intelligent Primary Care Centers in Chile

Primary care centers are establishments with elevated social relevance and high operational energy consumption. In Chile, there more than 628 family healthcare centers (CESFAM) have been built in the last two decades and with plans for hundreds more in the next few years. We revised the architecture, construction management and energy performance of five CESFAM centers to determine possible instances of overall improvement. Staff was interviewed, and state documents reviewed, which allowed the conceptualization of the architectonic and energy structure of the centers, as well as the process of implementation. At the same time, energy simulations were done for each one of the centers, controlling for different climates, construction solutions and orientations. Our study revealed that strategies employed by the primary healthcare centers in Chile have aided a progressive implementation of establishments with elevated costs and materialization times, as well as neglect for climatic conditions. These energy evaluations show relevant and consistent impacts of the architectural form and material conditions, especially in southern zones, demonstrating the need to work with shared knowledge resources such as BIM. There is a clear necessity to define technological, morphological and construction strategies specific to each climate zone in order to achieve energetically efficient and intelligent healthcare establishments

Curtain wall components for conserving dwelling heat by passive-solar means

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Architecture, 1983.MICROFICHE COPY AVAILABLE IN ARCHIVES AND ROTCHIncludes bibliographical references (p. 69-70).A prototype for a dwelling heat loss compensator is introduced in this thesis, along with its measured thermal performance and suggestions for its future development. As a heat loss compensator, the Sol-Clad-Siding collects, stores, and releases solar heat at room temperatures thereby maintaining a neutral skin for structures, which conserves energy, rather than attempting to supply heat into the interior as most solar systems do. Inhabitants' conventional objections to passive-solar systems utilized in housing are presented as a contrasting background. The potential of the outer component, a Trans-Lucent-Insulation as a sunlight diffuser and transmitter (65 to 52% of heating season insulation) and as a good insulator [0.62 W/(sq m) (°K) [0.11 Btu/(hr) (sq ft) (°F) 1] are described. The performance of the inner component, a container of phase-change materials as an efficient vertical thermal storage is discussed, and areas for future research are addressed. A very brief application of this passive-solar curtain wall system for dwellings is also given.by Doru Iliesiu.M.S

Geopolymer Betong med Mikrokapslede Faseendringsmaterialer for Energieffektive Bygninger

This study aims to develop new environmentally friendly construction materials with high energy storage capacity by using geopolymer concrete containing microencapsulated phase change materials (MPCM) to reduce energy consumption for buildings, which plays a key role to reduce global warming. The rheological behavior of microcapsule suspensions revile the important role of nonencapsulated phase change materials on the physical properties and structure of microcapsules. This initial investigation provided valuable information for selecting the right kinds of microcapsules to integrate into concrete. MPCM was integrated into Portland cement concrete (PCC) and geopolymer concrete (GPC), and a comparative analysis between PCC and GPC based on the thermal and mechanical properties was conducted. The influence of the hygroscopic nature of polymer shell, core/shell ratio and size of the microcapsules on the microstructure, thermal properties and compressive strength of geopolymer concrete was investigated and discussed. The combination of a polymer shell containing polar functional groups and a small size of MPCM has a significant impact on the dispersion of MPCM in the GPC matrix and the porosity enhancement of GPC, which causes a reduction of both thermal conductivity and compressive strength. In addition, a high core/shell ratio contributes to an increase of the energy storage heat capacity during the phase change and a reduction of compressive strength when PCM changes from solid to liquid state. A better understanding of the effect of microcapsule properties on GPC is important to further investigations to maximize the thermal performance and minimize the mechanical strength reduction of GPC containing MPCM for building applications. Thermal performance of GPC after incorporating MPCM was also investigated. Numerical modeling regarding the thermal performance of the materials was conducted and validated by experimental data. Systematic analysis of the effect of various climate conditions (outdoor temperature, maximum solar radiation) and MPCM-concrete design (wall thickness, MPCM concentration and core/shell ratio) on the energy efficiency of buildings using geopolymer concrete containing MPCM was examined. The possibility of utilizing GPC containing MPCM at the environmental conditions of Oslo and Madrid during a one year period was numerically evaluated. It was found that the powerv consumption for a heating/cooling system could be significantly reduced in both Oslo and Madrid after adding microcapsules into GPC walls. The wall orientations and the season have significant effect on energy efficiency of buildings, with the largest energy saving on the south and west facing walls and during summer.Formålet med dette studiet er å utvikle miljøvennlige konstruksjonsmaterialer med høy energilagringskapasitet ved å bruke geopolymerbetong som inneholder mikroinnkapslede faseovergangsmaterialer (MPCM) for å redusere bygningers energibehov og derved medvirke til redusert global oppvarming. Reologiske målinger på suspensjoner av mikrokapslene viser at faseovergangsmaterialer som ikke er innkapslet har stor innvirkning på de fysiske egenskapene og strukturen til mikrokapslene. Resultatene fra dette innledende studiet resulterte i ny kunnskap som er essensiell for valg av riktig type mikrokapsler for bruk i betong. MPCM ble blandet inn i Portland sement betong (PCC) og geopolymerbetong (GPC), og de termiske og mekaniske egenskapene til disse ble sammenlignet og analysert. Påvirkningen av de hygroskopiske egenskapene til polymerskjellet, kjerne/skjell ratioer og størrelsen til mikrokapslene på mikrostrukturer, termiske egenskaper og trykkfasthet til geopolymerbetong ble undersøkt. Kombinasjonen av et polymerskjell som inneholder polare grupper og mikrokapsler med små størrelser har en signifikant innvirkning på dispersjonen av mikrokapsler i GPC-matrisen og på porøsitetsøkningen til GPC. Dette reduserer både den termiske konduktiviteten og slagstyrken til GPC. I tillegg vil en høy kjerne/skjell ratio øke energilagringskapasiteten under faseovergangen og redusere slagfastheten når faseovergangsmaterialet går fra fast til flytende form. En bedre forståelse av effekten av egenskapene til mikrokapslene er viktig for videre studier for å maksimere den termiske energisparingen og minimere styrkereduksjonen av betongen for videre bruk som bygningsmaterialer. De termiske egenskapene til GPC med MPCM ble også undersøkt. Resultater av numerisk modellering av de termiske egenskapene til materialene ble validert ved sammenligning med eksperimentelle data. Effekten av forskjellige klimatiske forhold (utendørstemperatur, maksimal solstrålingsstyrke) og MPCM-betong design (veggtykkelse, MPCM-konsentrasjon og kjerne/skjell ratio) på energieffektiviteten til bygninger med geopolymerbetong med tilsatt MPCM ble systematisk studert og analysert. Muligheten for å bruke GPC som inneholder MPCM under klimaforholdene i Oslo og Madrid under en ett års periode ble nummerisk modellert. Resultatene viste at energikonsumpsjonen for et varme/kjølesystem ble signifikant redusert i både Oslo og Madrid når MPCM ble tilsattvii til vegger av GPC. Veggenes retning har en stor innvirkning på energieffektiviteten. Mest energi ble spart på syd- og vestvegger under sommeren

Using PCM to improve building's thermal performance

Due to EU and worldwide high energy consumption of the buildings stock, it is important to take measures to reduce these needs and, consequently, reduce the EU energy dependency as well as the greenhouse gas emissions. To improve the behaviour of the buildings, concerning thermal comfort of the occupants and energy performance, it is necessary to reduce the thermal amplitudes, the winter heat losses, the summer heat gains and to store the energy from solar gains. The thermal insulation and the thermal inertia play an important role in this. The use of phase change materials (PCM) is a way of achieving thermal mass without increasing the weight of the buildings and simultaneously improving the thermal comfort conditions inside buildings, by increasing thermal energy storage. The good thermal characteristics of PCM can be used, in new and existing residential or office buildings, as a passive way of saving energy and reducing running costs for both heating and cooling seasons. Therefore it is possible to achieve an adequate behaviour of buildings reducing the energy needs, using solar gains, night cooling and off-peak electricity and, at the same time, increasing the comfort conditions inside the buildings, reducing temperature fluctuations and peak temperatures. In the Mediterranean Countries the selection of the type and amount of PCM to be used is a challenge due to the different characteristics needed to achieve an adequate behaviour of the buildings during winter and summer periods. In this study, the use of micro and macro-encapsulated PCM in buildings was studied to evaluate the annual behaviour and to identify the amount of PCM needed to ensure a suitable thermal and energy performance of the buildings.The work was partially funded by the European Union (COST Action COST TU0802