Procjena optimizacijskog potencijala postavki dinamičke kontrole solarnih kombi-sustava pomoću računalnih simulacija

Before improving the control settings of solar heating systems with the help of sophisticated predictive algorithms, it is reasonable first to determine or at least estimate the theoretical potential of these improvements and then to decide if they are worthy of implementation. An approach is proposed in this paper which enables the estimation of the theoretical potential of the dynamic control settings optimization for solar heating combisystems. Dynamic optimization was carried out for a solar combisystem with a solar fraction of approximately 35% for the period of an entire year. The theoretical potential of the optimization of the boiler controller settings as well as the fluid mass flow in the collector loop and, consequently, in store loop, was estimated. The solar thermal combisystem was simulated in TRNSYS and optimization was carried out by the binary (n-ary) search algorithm programmed in GenOpt (Generic optimization software). The results showed that the extended fractional savings for the considered combisystem with dynamically optimized mass flow in the collector loop was only 0.3 percent points larger than that for the system with an optimized, but fixed mass flow. The optimization potential of the boiler controller settings turned out to be more promising, showing an improvement of 4.4 percentage points in thermal fractional savings for the system with two instant electrical heaters versus the initial system with a heated volume in the store.Prije poboljšanja kontrolnih postavki solarnog toplinskog sustava pomoću sofisticiranih prediktivnih algoritama, potrebno je prije odrediti ili procijeniti teoretski potencijal tih poboljšanja. U ovom radu je prikazan pristup koji omogućava procjenu teoretskog potencijala optimizacije postavki dinamičke kontrole za solarne kombi-sustave. Dinamička optimizacija je vršena za solarni kombi-sustav sa solarnim udjelom od 35% tokom cijele godine. Teoretski potencijal optimizacije postavki kontrole spremnika, kao i protok radnog fluida u kolektorskom krugu. Solarni toplinski kombi-sustav je simuliran u programu TRNSYS i optimizacija je vršena binarnim pretraživačkim algoritmom programiranom u GenOpt programu (Generic optimization software). Rezultati pokazuju da je ušteda na promatranom kombi-sustavu sa dinamički optimiziranim masenim protokom u solarnom krugu tek 0.3% veća nego kod istoga sustava sa optimiziranim, ali fiksnim masenim protokom radnog fluida. Optimizacijski potencijal postavki kontrole spremnika je pokazao bolje rezultate, postigavši 4.4% veću uštedu toplinske energije za sustav sa dva električna grijača

Procjena optimizacijskog potencijala postavki dinamičke kontrole solarnih kombi-sustava pomoću računalnih simulacija

Before improving the control settings of solar heating systems with the help of sophisticated predictive algorithms, it is reasonable first to determine or at least estimate the theoretical potential of these improvements and then to decide if they are worthy of implementation. An approach is proposed in this paper which enables the estimation of the theoretical potential of the dynamic control settings optimization for solar heating combisystems. Dynamic optimization was carried out for a solar combisystem with a solar fraction of approximately 35% for the period of an entire year. The theoretical potential of the optimization of the boiler controller settings as well as the fluid mass flow in the collector loop and, consequently, in store loop, was estimated. The solar thermal combisystem was simulated in TRNSYS and optimization was carried out by the binary (n-ary) search algorithm programmed in GenOpt (Generic optimization software). The results showed that the extended fractional savings for the considered combisystem with dynamically optimized mass flow in the collector loop was only 0.3 percent points larger than that for the system with an optimized, but fixed mass flow. The optimization potential of the boiler controller settings turned out to be more promising, showing an improvement of 4.4 percentage points in thermal fractional savings for the system with two instant electrical heaters versus the initial system with a heated volume in the store.Prije poboljšanja kontrolnih postavki solarnog toplinskog sustava pomoću sofisticiranih prediktivnih algoritama, potrebno je prije odrediti ili procijeniti teoretski potencijal tih poboljšanja. U ovom radu je prikazan pristup koji omogućava procjenu teoretskog potencijala optimizacije postavki dinamičke kontrole za solarne kombi-sustave. Dinamička optimizacija je vršena za solarni kombi-sustav sa solarnim udjelom od 35% tokom cijele godine. Teoretski potencijal optimizacije postavki kontrole spremnika, kao i protok radnog fluida u kolektorskom krugu. Solarni toplinski kombi-sustav je simuliran u programu TRNSYS i optimizacija je vršena binarnim pretraživačkim algoritmom programiranom u GenOpt programu (Generic optimization software). Rezultati pokazuju da je ušteda na promatranom kombi-sustavu sa dinamički optimiziranim masenim protokom u solarnom krugu tek 0.3% veća nego kod istoga sustava sa optimiziranim, ali fiksnim masenim protokom radnog fluida. Optimizacijski potencijal postavki kontrole spremnika je pokazao bolje rezultate, postigavši 4.4% veću uštedu toplinske energije za sustav sa dva električna grijača

Otkrivanje i dijagnoza kvarova u velikim solarnim toplinskim sustavima

A four-step concept for fault detection and fault diagnosis for solar thermal systems has been developed in the framework of the ongoing research activities at Kassel University. This concept is able to combine different general approaches for fault detection and fault diagnosis in one structure. Additionally it introduces a systematic categorization of information and a more precise terminology by distinguishing between element sensor values, measured values, features and symptoms.Koncept u četiri koraka za otkrivanje i dijagnozu kvarova (FDD) u velikim solarnim toplinskim sustavima je razvijen u okviru tekućih istraživačkih aktivnosti na Sveučilištu Kassel. Ovaj koncept kombinira različite opće pristupe za otkrivanje i dijagnozu kvarova u jednoj strukturi. Osim toga, uvodi se sustavna kategorizacija podataka i preciznija terminologija prema razlikovanju između veličina dobivenih iz osjetnika, mjerenih veličina, svojstava i simptoma za pojedine elemente sustava

Techno-economic evaluation of electricity price-driven heat production of a river water heat pump in a German district heating system

Large scale heat pumps (HP) are an important technology that will link district heating (DH) systems to the electricity sector in future smart energy systems. This paper examines the feasibility of the integration of a river water HP at a combined heat and power plant in Germany. It is part of a more extensive study about the transformation of a DH system in an urban district towards a 4th generation DH system. The focus is on operational characteristics and economic efficiency of electricity price-driven heat production. A novel method for estimating the coefficient of performance (COP) of two-stage ammonia HPs based on the difference between sink and source temperature is presented. The HP achieves a seasonal COP in the range of 3.4 to 3.7. The 15-year simulation with the software energyPRO shows that electricity-price driven operation is especially relevant for lower heat loads during the non-heating season. The correlation between volatility of electricity market price change and flexible operation is analysed. Finally, the levelized cost of heat for four designs with heat outputs of the HP from 4.7 MWth to 6.1 MWth and increasing storage sizes are compared. The results indicate that electricity costs are reduced in more flexible systems, but cost parity to the minimum dimensioning is not yet reached with the underlying economic framework conditions. However, the parameters that benefit the economic efficiency of more flexible systems are discussed

SolNet:PhD-scholarships and courses on solar heating

AbstractSolNet, founded in 2006, is the first coordinated International PhD education program on Solar Thermal Engineering. The SolNet network is coordinated by the Institute of Thermal Engineering at Kassel University, Germany. The network offers PhD courses on solar heating and cooling, conference-accompanying Master courses, placements of internships, and PhD scholarship projects. A new scholarship project, “SHINE”, will be launched in autumn 2013 in the frame work of the Marie Curie program of the European Union (Initial Training Network, ITN). 13 PhD-scholarships on solar district heating, solar heat for industrial processes, as well as sorption stores and materials will be offered, starting in December 2013. Additionally, the project comprises a training program with five PhD courses and several workshops on solar thermal engineering that will be open also for other PhD students working in the field. The research projects will be hosted by six different universities and five companies from all over Europe

Solar Hot Water Systems for Public Outdoor Swimming-Pools

Abstract Over a period of two seasons the hot water consumption, most of it for showers, and various meteorological quantities were measured minutely in the Marburg outdoor swimming-pool (about 100000 visitors/a). With the load demand profile TRNSYScalculations were carried out, which delivered criteria for dimensioning solar hot water systems in public outdoor swimming-pools

Data Repository - Heat Load Profiles in Industry and the Tertiary Sector: Correlation with Electricity Consumption and Ex Post Modelling

This work was supported by the German Federal Ministry for Economic Affairs and Energy within the framework of the 7th Energy Research Program [project: “AnanaS”, grant number 03ETW014A]

Annual industrial and commercial heat load profiles: modeling based on k-Means clustering and regression analysis

Gefördert durch den Publikationsfonds der Universität Kasse

Heat Load Profiles in Industry and the Tertiary Sector: Correlation with Electricity Consumption and Ex Post Modeling

Gefördert durch den Publikationsfonds der Universität Kasse