Simulation models and performance assessment of district heating substations

Development of new technologies and methodologies regarding district heating substation operational control strategies are increasingly found nowadays. At the same time a great number of modern buildings are provided with energy monitoring and control systems which supervise and collect operating data from different energy components. Accordingly, an exemplary district heating systems is being implemented in the city of Kortrijk in Belgium, as part of a demonstration zero-carbon neighborhood. This study deals with the energy performance assessment of one of the systems component -the consumer substationinstalled in this low-temperature district heating system. A comparative analysis of the energy performance with several existing district heating substations was carried out. Three different district heating substation models are set up (using TRNsys) for investigation of the gross energy use, energyefficiency and comfort issues. In order to evaluate the performance of the analyzed substations two scenarios concerning the space heating system (radiator or floor heating system) were considered. The study aims to investigate the impact of different operational circumstances on the performance of district heating substations. The study generate understandings for energy saving operational strategies to be developed. Results indicate that the design concept together with a suitable selection of the substation has an important impact on the energy performance of the entire system

Building energy performance characterisation based on dynamic analysis and co-heating test

A demonstration zero-carbon neighborhood is being raised in the city of Kortrijk, Belgium in the framework of the ECO-Life project within the CONCERTO initiative. A holistic approach is applied to achieve the zero-carbon targets, considering all aspects that are relevant for energy supply. Accordingly, alongside the integration of renewable energy sources in the community, a low-temperature district heating system is being implemented to cover the heat demand. In this context, full scale testing of building thermal performances, by use of a co-heating test and flux measurements, can be useful to analyze the thermal performance of the building envelope in situ. For that reason, as part of a more general study regarding low-energy building, co-heating test, blower-door test and flux measurements in several apartments were executed. Therefore, the paper focuses on characterization of the thermal dynamic behavior of an apartment, as a first approximation of data analysis of a monitoring system involving whole buildings. In addition, in the present study, the capability of linear regression techniques to characterize the thermal behavior of a newly built low-energy apartment in Belgium is investigated. The strengths and weaknesses of different models are identified. The limitation and possibilities of regression models are evaluated in the face of their applicability as a simplified building equation model. The identified model structure is going to be used within a complex simulation model of an entire district heating system with around 200 dwelling. Finally, the potential of this kind of regression models to be used as part of the operational control scheme of a district heating system is presented

Actual energy performance of a zero-carbon neighbourhood

The evolution towards zero-energy buildings and districts brings along uncertainties about the operational performance, strengths and weaknesses of these technologies, that are often new and unfamiliar to both the designers, owners and users. In Kortrijk, an exemplary zero-carbon neighbourhood is designed, built and evaluated in the framework of a European demonstration project ECO-Life ‘Sustainable zero-carbon ECO-town developments improving quality of life across EU’. The neighbourhood counts about 200 dwellings in highly energy-efficient buildings with different ventilation technologies and collective RES based on solar, biomass or aero-thermal energy. During the building process and the first years of operation, the energy performance of the neighbourhood is evaluated after intensive monitoring and testing by Ghent University’s research group of building physics, construction and services. This paper presents two focal points of the research: the energy demand of the buildings and the interaction with the occupants, and the energy performance of the neighbourhoods' low-temperature district heating system

Thermal comfort and indoor air quality on end-user satisfaction level evaluation in a Nearly Zero Carbon neighbourhood

End-user satisfaction studies in residential buildings has to be approached combining the user’s perspective and technical criteria to consider the complex interactions influencing the building energy performance. Therefore, in this study the physical characteristics of dwellings and their environments are assessed, user satisfaction is examined, and the relationship between them is investigated. The study aims to illustrate the end-user satisfaction in exemplary high performance buildings and to investigate how the users are interacting with these buildings. Examination of the building performance, thermal comfort and indoor air quality are the main focal points of the work. In general, results reflect a significant improvement on the satisfaction level of the inhabitants with the comfort of the dwelling after the refurbishment of the district. Findings from the cross-analysis of both surveys and measurements are used to further refine conclusions and identify the driving factors of the interrelationship between building performance and end-user satisfaction

Identification of energy use time patterns of occupied dwellings using smart meter data

The increasing application of smart and digital energy meters leads to an increasing availability of frequent -e.g. hourly- and long-term measurements of the actual energy use in occupied buildings. In the resulting energy use time series, the diurnal fluctuations in energy use are recognised and similarities between diurnal profiles for various days are observed. These recurring profiles are called energy use time patterns and they are a result of various phenomena, such as patterns in the building use, occupational schedules, settings of the system control, short-term weather dynamics etc. These energy use time patterns can provide a better understanding of the energy use, which is useful in many fields including energy feedback, fault detection and energy auditing. In order to identify and characterise energy use time patterns for large data-sets, an automated approach is needed. This paper proposes a methodology for automated mathematical recognition of energy use time patterns based on cluster analysis. Secondly, a methodology to characterise the identified patterns in function of external variables is proposed, using classification analysis techniques. The methodologies allow an automated identification and characterization of energy use time patterns, allowing a better understanding of the variations and changes in building energy use and their relation to weather conditions and calendar aspects

Environmental impact of timber frame walls

Timber frame walls are increasingly applied nowadays due to the stringent energy performance requirements of buildings. The aim of this study was to investigate the environmental impact of this type of construction. Therefore, a cradle to gate analysis was used. The study consists of three consecutive steps. First the impact of the constituting materials was studied. The results show e.g. that the environmental impact of LVL studs is significantly larger than that of SLS studs or I-joists. Based on these results on material level, in the second stage three timber frame walls were designed and evaluated. All walls had the same thermal performance. When comparing the results, it was noted that the environmental impact of the wall with the highest impact is three times larger than that of the wall with the lowest impact. Finally, the study also looked at the additional impact of tapes for guaranteeing the air tightness of timber frame constructions and at the impact of fasteners. It could be concluded that the impact of tapes is negligible when looking at the total impact of the wall (less than 1%). The fasteners on the other hand, lead to an increase in environmental impact with almost 20%

Het belang van commissioning in energetisch performante woningen: de CO2-neutrale woonwijk Venning

In de context van het Europese CONCERTO ECO-Life project wordt de Kortrijkse Venningwijk getransformeerd tot een CO2-neutrale woonwijk met 196 woningen. Aan de gebouwschil en de technische installaties werden hoge energieprestatie-eisen opgelegd en een hedendaags lage temperatuur warmtenet voorziet de volledige wijk van warmte uit biomassa. Een belangrijke doelstelling van het project is om de hoge niveaus van energieprestatie, comfort en leefkwaliteit ook in realiteit te verwezenlijken. Om de reële werking van de gebouwen en installaties in gebruikstoestand te evalueren, worden commissioning-activiteiten verdergezet tijdens de eerste jaren van ingebruikname, en worden ondermeer de energiestromen permanent gemonitord