Search Results (5)

The Fourth Industrial Revolution forms a smart grid with diverse sources of energy through the interconnectivity of data. Buildings that were previously the biggest users of energy are now becoming energy producers. Yet, buildings are also continually changing. The ecological definition of buildings, in addition to the building itself, includes solar panels and geothermal energy storage. The need for decarbonization and energy-efficiency brought about the implementation of heat pumps in buildings. The most economic type of heat pump is a water-sourced heat pump with hot and cold tanks or a connection to the District Energy System. Monitoring using building automatics allows HVAC optimization in the occupancy stage. Until the SARS-CoV-2 pandemic, the EU and the US differed in their air handling methodology, but the pandemic showed the limitations of both approaches and led to the creation of a new, integrated approach. These new ventilation systems, based on filtration instead of dilution, come together with decarbonization and the demand for new and retrofitted buildings to be smart, have zero emissions and excellent indoor environments, and be affordable. To fulfill these conditions, design teams must extrapolate experience with passive houses and introduce expertise in building automatic controls (BAC). The authors analyze the heating cooling and ventilation aspects of dwellings in a technology called Ecological Thermo-Active (ETA) technology that can also be applied to the interior retrofitting of buildings, including those with historic facades. The building “with classic form and ultramodern function” is an example of this changing design paradigm. Full article

To address the huge market of renovation of multi-apartment buildings, minimal-invasive decentral serial-renovation solutions are required. One major challenge in the design of decentral heat pumps is to find the optimal balance between, on one hand, compactness and pleasant design, and on the other hand, efficiency and minimal sound emissions. A comprehensive holistic design and optimization process for the development of decentral heat pumps, from the component level, to the system level, and up to the building level, is developed. A novel façade-integrated speed-controlled exhaust air to supply air heat pump combined with a mechanical ventilation system with heat recovery and recirculation air was developed and simulated in a reference flat. Compared to a traditional supply air heat pump without recirculation, it shows only slight performance improvement, but allows significantly better thermal comfort and control, independently from the hygienic air flow rate and from the heating and cooling loads. Detailed measurement and simulation results are presented for several functional models with heating power of around 1 kW up to 2.5 kW. The design was optimized by means of CFD simulations to allow for low pressure drop, homogeneous flow, and low sound emissions. Moreover, mock-ups of innovative façade-integrated heat pump outdoor units are presented. Full article

In Canada, more than 80% of energy in the residential sector is used for space heating and domestic hot water (DHW) production. This study aimed to model and compare the performance of four different systems, using solar energy as a renewable energy source for DHW production. A novel microchannel (MC) solar thermal collector and a microchannel-based hybrid photovoltaic/thermal collector (PVT) were fabricated (utilizing a microchannel heat exchanger in both cases), mathematical models were created, and performance was simulated in TRNSYS software. A water-to-water heat pump (HP) was integrated with these two collector-based solar systems, namely MCPVT-HP and MCST-HP, to improve the total solar fraction. System performance was then compared with that of a conventional solar-thermal-collector-based system and that of a PV-resistance (PV-R) system, using a monocrystalline PV collector. The heat pump was added to the systems to improve the systems’ efficiency and provide the required DHW temperatures when solar irradiance was insufficient. Comparisons were performed based on the temperature of the preheated water storage tank, the PV panel efficiency, overall system efficiency, and the achieved solar fraction. The microchannel PVT-heat pump (MCPVT-HP) system has the highest annual solar fraction among all the compared systems, at 76.7%. It was observed that this system had 10% to 35% higher solar fraction than the conventional single-tank solar-thermal-collector-based system during the wintertime in a cold climate. The performance of the two proposed MC-based systems is less sensitive than the two conventional systems to collector tilt angle in the range of 45 degrees to 90 degrees. If roof space is limited, the MCPVT-HP system is the best choice, as the MCPVT collector can perform effectively when mounted vertically on the facades of high-rise residential and commercial buildings. A comparison among five Canadian cities was also performed, and we found that direct beam radiation has a great effect on overall system solar faction. Full article

Due to recent changing climate conditions and glazing of building facades, a rapid increase in the requirement of cooling systems can be observed. Still the main energy source for cooling are fossil fuels. In this article we report on a fully integrated approach of running a heat pump for actively cooling a test room by electric energy, generated by facade integrated photovoltaic modules, the “COOLSKIN” system. Photovoltaic facades are emission free in the operation phase, efficiently utilize otherwise unused surfaces, and portray a favorable method in terms of construction physics and the architectural design of buildings. Compared to existing systems, COOLSKIN is an entirely autonomous system where every component is located inside the facade structure which introduces a high level of plug and play character. In this article the analysis of the electric performance of the COOLSKIN system with respect to its operation under different environmental conditions is presented. The over all system efficiency was determined with 73.9%, compared to a simulated efficiency (PV*SOL) of 68.8%, and to the theoretically expected value of 85%. The system behavior is evaluated depending on photovoltaic output and the cooling demand. The analysis shows that a considerable amount of cooling demand could be decentrally fulfilled with photovoltaic energy, but environmental conditions as well as system layout have a considerable impact on system performance. Full article

Building envelopes can play a crucial role in building improvement efficiency, and the adoption of Phase Change Materials (PCMs), coupled with transparent elements, may: (i) allow a better control of the heat flows from/to the outdoor environment, (ii) increase the exploitation of solar energy at a building scale and (iii) modulate light transmission in order to prevent glare effects. Starting from a literature review, focused on experimental works, this research identifies the main possible integrations of PCMs in transparent/translucent building envelope components (in glazing, in shutters and in multilayer façade system) in order to draw a global picture of the potential and limitations of these technologies. Transparent envelopes with PCMs have been classified from the simplest “zero” technology, which integrates the PCM in a double glass unit (DGU), to more complex solutions—with a different number of glass cavities (triple glazed unit TGU), different positions of the PCM layer (internal/external shutter), and in combination with other materials (TIM, aerogel, prismatic solar reflector, PCM curtain controlled by an electric pump). The results of the analysis have been summarised in a Strengths, Weakness, Opportunities and Threats (SWOT) analysis table to underline the strengths and weaknesses of transparent building envelope components with PCMs, and to indicate opportunities and threats for future research and building applications. Full article