Potential Performance Enhancement of a Solar Combisystem with an Intelligent Controller

Solar thermal systems in residential buildings are generally controlled by two-level controllers, which activate solar thermal or at times with low solar radiation auxiliary energy supply into a thermal storage. Simple controllers do not have any information on actual or expected solar radiation. This leads to interference of auxiliary- and solar heat supply, which reduces the share of solar thermal energy fed into the thermal storage. Increasing accuracy of weather forecast data suggests incorporation of this information in the control algorithm. This work analyzes the maximum potential performance enhancement when applying such an intelligent predictive control. Two solar thermal systems with one auxiliary source respectively are designed in TRNSYS - these systems represent the base case. Further, a number of simulations are conducted with minor variations for the plant parameters - this gives generic results for different system configurations. In addition, each system configuration is altered to mimic the behavior of a plant with intelligent predictive control. Comparison of results indicates an improvement potential up to 10% for annual solar fractions and up to 30% for monthly solar fractions. The performance bound with respect to the annual auxiliary energy savings is approximately 8%

COOLSAN Kältetechnische Sanierungskonzepte für Büro- und Verwaltungsgebäude

Energie-Umweltmanagemen

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

On the Typology, Costs, Energy Performance, Environmental Quality and Operational Characteristics of Double Skin Façades in European Buildings

The project BESTFAÇADE, sponsored by the Energy Intelligent Europe programme of the European Union, and led by MCE-Anlagenbau, Austria, accumulated the state of the art of double skin façades (DSFs) in seven European countries (Austria, Belgium, France, Germany, Greece, Portugal and Sweden). Twenty-eight façades of different buildings in all partner countries of BESTFAÇADE have been analysed for the aspects, types of façade in different countries, DSFs in different climatic regions of Europe, existing simulations and measurements, thermal behaviour, indoor air quality, comfort, user acceptance, energy demand and consumptions, control strategies, integrated building technology, cost (investment, maintenance and operation), resource conservation, environmental impact, comparison to conventional glass façades (CGFs), integration of renewable energy sources into DSFs, as well as non-energy related issues, such as, acoustics, aesthetics, fire protection, moisture, corrosion, durability, maintenance and repair. Most of the buildings are office buildings, followed by schools and service buildings. Nearly all of the buildings have mechanical ventilation systems, and both heating and cooling are performed mostly by air heating/cooling systems. The types of façades are mainly multi-storey and corridor types; in Belgium juxtaposed modules are frequently used. The façade gaps are mostly naturally ventilated (except for Belgium, where the indoor air is led by mechanical ventilation via the gap to the centralized air handling unit). The shading is performed mainly with Venetian blinds located in the gap. Unfortunately data on energy demand and temperatures are infrequently measured and rarely available. The cost of DSFs is significantly higher than conventional façades