A building integrated solar thermal collector with active steel skins

Integrated HVAC and DHW production systems for Zero Energy Buildings

The aim of this study was to test a tri-partite gas cooler for CO2 heat pumps (5-13 kW). The proposed heat exchanger allowed the simultaneous and separate production of space heating and domestic hot water with an integrated design, simplifying the heat pump layout and piping requirements. The experimental campaign was dedicated to the performance of the gas cooler at various operation conditions. These operation modes are: i) only space heating, ii) only domestic hot water iii) simultaneous production of domestic hot water and space heating. The results of the test campaigns were analysed in order to determine potential improvements or required redesign of the heat exchanger. The heat exchanger solution was integrated to novel prototype of tri-generation CO2 heat pump system.

The next level of energy performance of new buildings within the European Union will be the Nearly Zero-Energy Building (NZEB). A lot of work has been spent on pilot and demonstration buildings on this and also even higher energy performance levels throughout all EU countries. However, most of the high performance buildings realised so far result in higher investment costs when compared to the current national minimum energy performance requirements. The considerably higher investment costs are one of the main barriers to the early application of the NZEB-level in Europe. The EU H2020 project CoNZEBs works on technical solution sets that result in lower investment costs for NZEBs, bringing the costs close to those of conventional new buildings. The focus is on multi-family houses. In each of the four participating countries Germany, Denmark, Italy and Slovenia a team of researchers is analysing which sets of marketready technologies at the building envelope, the services systems for heating, domestic hot water, ventilation and cooling (where required) in combination with renewable energy systems can fulfil the NZEB requirements at lower costs than those incurred by the national mainstream NZEB application. Additional efforts are being spent on the life-cycle costs and the life-cycle analysis of the solution sets, as well as on the impact of future developments of primary energy factors, energy costs and technology efficiencies.

Influence of the refrigerant charge in an R407C liquid-to-water heat pump for space heating and domestic hot water production

The multi-functional variable refrigerant flow (MFVRF) system is a promising solution to meet the UE objective that all new buildings shall be nearly zero-energy buildings (NZEBs). In particular, it is a high-efficiency system able to supply space cooling, space heating and domestic hot water (DHW) production simultaneously in different zones allowing also for waste heat recovery. The aim of this work is to implement a novel dynamic model of the MFVRF in EnergyPlus 9.4 in order to assess its final energy consumption and to account for the heat recovered when working in cooling mode to be used for DHW production. The developed model is employed to compare the performance of a MFVRF system in a multifamily residential building of 858 m2 with that of a conventional solution. The simulations are performed for two different climate conditions in Spain and two different DHW consumption temperatures. The results show significant energy savings achieved with the MFVRF system and DHW being consumed at 60 ºC for both Madrid (63.82%) and Seville (51.8%). Additionally, energy savings were even further enhanced for DHW being consumed at 45 ºC for Madrid (73.69%) and for Seville (70.71%). It is concluded that part of the annual DHW energy demand is covered by heat recovery for Madrid (4.96%) and Seville (5.69%) at a DHW consumption temperature of 60 ºC and for Madrid (6.42%) and Seville (8.96%) at a DHW consumption temperature of 45 ºC.

This paper examines, from the energetic point of view, the design process of a stand-alone house as a microgrid (MG) in Rome, which inhabited by a family of four people. The house is equipped with all the electrical devices necessary to ensure comfort conditions and to achieve a Nearly Zero Energy Building (NZEB). In the island mode, the electric current of the building is supplied by a photovoltaic (PV) system and a battery energy storage system (BESS). All the electrical users present in the house are characterized by a high energy class. In order to make the house working in island mode from an electric and thermal point of view, has been decided to install a heat pump, electrically driven, for the production of domestic hot water (DHW) to feed the radiators and for domestic uses. For this MG case study, a standard load profile and an optimized load profile have been analyzed. The comparison between the two different scenarios has been carried out by the optimization software. The results show an improvement of all the economic and technical parameters in the optimized case compared to the standard case, due to a better exploitation of the energy produced by the PV system. Furthermore, the size of the components with the installation of a Building Automation and Control System (BACS) in the optimized case, is slightly reduced leading to a lower cost of operation and investment.

Theoretical and Experimental Study of a Thermally Driven Heat Pump Based on a Double Organic Rankine Cycle

This paper describes the development of a new facility for testing building envelope systems called Building Envelope Test cell (BETcell), implemented at Politecnico di Torino. The test facility is aimed at characterizing the thermal performance of building envelope components and systems in realistic boundary conditions (real world climatic conditions), but yet controllable. This becomes particularly important when the thermal performance of the building envelope system depends on the boundary conditions (i.e. responsive building envelope elements and multifunctional facades) and when the characterization of the whole facade system is required, in order to reduce the resources needed for outdoor testing. The integration with an outdoor test facility and a guarded hot plate enable a complete thermal characterization of building envelope systems, components and/or materials. The aim of the BETcell is to provide the building industry with an instrument that will enhance the development of innovative and low-energy building envelopes

Generalizable occupant-driven optimization model for domestic hot water production in NZEB

Performance analysis of a R407C liquid-to-water heat pump: Effect of a liquid–vapor heat exchanger and domestic hot water production

Experimental analysis of a ground source heat pump in a residential installation after two years in operation

The present study focuses on the optimizing of passive energy efficiency measures and the dimensioning of renewable energy systems to improve the energy performance and achieve net zero-energy building. A set of building envelope parameters have been considered including window-to-wall ratio, air change rate, transmission coefficient of the external surfaces and absorption coefficient of the solar radiation of the external surfaces. On the other hand, the considered renewable energy systems include a residential wind power system and a photovoltaic system for the production of electricity as well as a solar thermal collector for the production of domestic hot water. In order to obtain a reliable combination and an optimal solution, a multi-objective optimization was carried out. The obtained results show that more than 30% of energy saving can be achieved and 50% of building energy load can be covered instantly by renewable energy systems in Tetouan (Morocco).

Sustainable and energy-efficient domestic hot water systems: A review

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