Polymeric Materials in Solar-thermal Systems - Performance Requirements and Loads

AbstractA major basic problem in selecting appropriate polymeric materials and processing technology routes is related to the lack of well-defined functional and performance requirements on the component level and to material property requirements on the specimen level.Hence, in a first step several reference climate regions were defined for pumped systems (continental (Graz/Austria), moderate climate (Beijing/China)) and non-pumped systems (Mediterranean (Athens/Greece), hot and dry (Pretoria/South Africa), hot and humid (Fortaleza/Brazil)), respectively. For each of these reference regions various solar-thermal plant types (e.g., domestic hot-water systems for single family houses (pumped and thermosiphon); domestic hot-water systems for multi-family houses; solar combi-systems for domestic hot-water and space heating (pumped) were pre-defined and evaluated and optimized virtually by modelling and simulation.To determine performance requirements on the component level and to derive material property requirements on the specimen level all-purpose modelling and design tools for collectors were implemented and used which allow for the description of temperature profiles, stagnation conditions, efficiency curves, pressure losses, distribution of fluid and heat flow and the thermal and hydraulic optimisation of the whole collector

Integrating plus energy buildings and districts with the eu energy community framework:Regulatory opportunities, barriers and technological solutions

The aim of this paper is to assess opportunities the Clean Energy Package provides for Plus Energy Buildings (PEBs) and Plus Energy Districts (PEDs) regarding their economic optimization and market integration, possibly leading to new use cases and revenue streams. At the same time, insights into regulatory limitations at the national level in transposing the set of EU Clean Energy Package provisions are shown. The paper illustrates that the concepts of PEBs and PEDs are in principle compatible with the EU energy community concepts, as they relate to technical characteristics while energy communities provide a legal and regulatory framework for the organization and governance of a community, at the same time providing new regulatory space for specific activities and market integration. To realize new use cases, innovative ICT approaches are needed for a range of actors actively involved in creating and operating energy communities as presented in the paper. The paper discusses a range of different options to realize PEBs and PEDs as energy communities based on the H2020 EXCESS project. It concludes, however, that currently the transposition of the Clean Energy Package by the EU Member States is incomplete and limiting and as a consequence, in the short term, the full potential of PEBs and PEDs cannot be exploited

Automatic thermal model identification and distributed optimisation for load shifting in city quarters

Buildings with floor heating or thermally activated building structures offer significant potential for shifting the thermal load and thus reduce peak demand for heating or cooling. This potential can be realised with the help of model predictive control (MPC) methods, provided that sufficiently descriptive mathematical models of the thermal characteristics of the individual thermal zones exist. Creating these by hand is infeasible for larger numbers of zones; instead, they must be identified automatically based on measurement data. In this paper an approach is presented that allows automatically identifying thermal models usable in MPC. The results show that the identified zone models are sufficiently accurate for the use in an MPC, with a mean average error below $1.5{\rm \; K}$ for the prediction of the zone temperatures. The identified zone models are then used in a distributed optimisation scheme that coordinates the individual zones and buildings of a city quarter to best support an energy hub by flattening the overall load profile. In a preliminary simulation study carried out for buildings with floor heating, the operating costs for heating in a winter month were reduced by approximately 9%. Therefore, it can be concluded that the proposed approach has a clear economic benefit

Existing PVT systems and solutions

Throughout the world, many new technologies and projects are currently being undertaken to assist in the reduction of fossil fuel consumption. While the focus has been in th eelectrical and transport sector, significant progress has been made in the combined realm of renewable electricity and heat production based on photovoltaic thermal collectors (PVT). In several European countries the PVT market is picking up speed.The possible applications for PVT-collectors are very varied and range from e.g. swimming pool heating to solar heat for industrial processes. Many of the already installed PVT systems are small in nature, but are able to satisfy a huge fraction of the overall onsite thermal and electrical energy demand, and serve as a good demonstration of the potential fuel savings. A good, though not all encompassing, survey of currently operating PVTplants has been conducted. Within this survey, 22.920 PVT-systems were identified. A Global market overview and a sample of installed PVT systems with various PVT-collector types are exhibited in the following chapters, spanning most of the relevant PVT applications. These case studies include a general description of the solar installation, the overall heat supply concept and integration scheme, and other pertinent information to provide a deeper understanding of the subtleties of such projects