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Based on an analysis of building processes to date, this paper proposes two ways to make Building Information Modelling (BIM) and with it complex building processes less expensive and more reliable. First, existing experience with building processes that include building-integrated solar systems is analysed, as they are one example for buildings with high energy-saving goals. Based on the analysis, the authors propose to include a new property set and functions in machine code in the next version of the Industry Foundation Classes (IFC). For the machine-code functions, several formats are proposed and the advantages and disadvantages of the proposed IFC extensions are discussed. For simple conventional building components, the existing IFC version 4 seems appropriate. Buildings with innovations that add complexity to the building process can profit most by the savings generated by exchanging machine-code functions. In building processes to date, much information is not shared because of proprietary matters. Functions in machine code can provide the necessary confidentiality so that more capabilities can be exchanged between the stakeholders. Models based on machine-code functions can be updated much faster than detailed models with many parameters. With machine-code functions, advantage can be taken of the greater accuracy of detailed models, as long as they are fast and easy to use. The modularity of the functions stimulates competition between alternative approaches, which makes simulation models less expensive. Finally, exchanging a closed, validated simulation model in machine code introduces a much lower risk of error than exporting and importing complex simulation models.

Building-integrated solar thermal systems (BIST) outperform building-added solar thermal systems (BAST) due to smaller heat losses at the back of the collector. BIST offer economic advantages, too. The insulation behind the collector can be used to reduce the heating demand of the building as well as to increase the solar thermal yield. Therefore, less material and labour are needed. Of course, the energy flux to the building interior needs to be considered. This energy flux depends in general on the operation of the collector as well as on the irradiance. Several innovative solar thermal building skins have been modelled in detail to analyze this coupling between the active building skin and the building. However, planners need an easy approach to include BIST into their calculations. Often, there is not enough budget to measure and model the new facade. This paper presents several new and simple models which are more accurate than neglecting the coupling to the building and which are less complex than detailed physical models.

In the building sector there is a new tendency to integrate solar thermal technologies into buildings. These systems are known as Building-Integrated Solar Thermal (BIST) and offer several advantages in comparison with the Building-Added (BA) installations. The present study is a critical review on modelling of BIST systems and also covers other types of BI solar configurations such as Photovoltaic (PV) and Photovoltaic/Thermal (PVT) in order to provide a better view of the literature. For some instances where the model and/or the system are interesting, BA systems are also cited. The studies are presented into groups, depending on the type of modelling (energetic, thermal, optical, etc.) and based on the technical characteristics of each system (solar collector, skin facade, etc.). The present article is the first part of an investigation about BIST modelling and it gives emphasis on the studies which focus on the interaction between BIST and building (coupled building/system configuration). The study reveals that majority of the modelling are about BIPV and skin facades while there are very few studies on BIST systems. Thereby, more investigations on energetic, thermal, optical simulations for BIST installations particularly for active systems (e.g. active solar thermal collectors) are necessary. On the other hand, innovative ideas such as systems with phase change materials, nanofluids, concentrating solar thermal could also be examined as a future prospect for modelling/simulation. The study also shows that further development of environmental models on BIST systems is required.

As part of the Shagaya Renewable Energy Master Plan in Kuwait, the presented study describes the methodology developed and applied for the optimization of the technology mix for a 2̊GW, 1002km2 renewable energy park. Scenarios with different focuses for the technology mix were developed, selecting from 14 technology options (three wind, five PV and six CSP) and emphasizing either high peak load supply, high overall annual electricity production or low levelized cost of electricity. An optimization procedure that uses a general pattern search algorithm implemented in the software GenOpt was used to maximize a score calculated from eight criteria. These were determined in a social-techno-economic evaluation, which included performance simulations of every technology option for the allocated site in Kuwait. Besides the available land area, the capacity credit of the installed technology mix was included as an additional boundary condition. 2010 was selected as base year since it was the most recent year for which both high quality meteorological and electricity demand data was available. The results for all considered scenarios are presented in this paper, with the one that was chosen as final result of the master plan comprising 136̊MW wind power, 614̊MW of PV and 1250̊MW of CSP. Furthermore, the study showed that thermal storage is indispensable to serve peak demand hours and a diverse technology mix is important to achieve a high capacity credit.

Building-Integrated Solar Thermal (BIST) systems are a new tendency in the building sector and provide multiple advantages in comparison with the Building-Added (BA) installations. The present paper is a critical review about solar system modelling with emphasis on BIST configurations. The review includes also BI solar systems which produce electricity (Photovoltaic: PV) or both electrical/thermal energy (Photovoltaic/Thermal: PVT) in order to provide a more complete view of the current literature. For some cases where the system and/or the model are of great interest, BA configurations are also cited. The references are presented separated into groups, based on the model type (thermal, energetic simulation, etc.) and system characteristics (solar thermal collector, skin facade, etc.). The present review is the 2 nd part of an investigation about BIST modelling and it focuses on modelling studies about the solar system itself. The results reveal that most of the investigations about BI configurations refer to PVT, PV or skin facades while there are few studies about BIST systems. Thus, there is a need for more investigations about BIST installations, especially for active configurations which could provide thermal (or electrical/thermal) energy for building energy requirements. On the other hand, more optical simulations as well as more life-cycle analysis studies about BIST are also necessary. Taking into account the findings of the 1 st part of the present investigation, majority of the BIST modelling studies focus on the system itself; thereby, more investigations which examine the system in conjunction with the building are needed. Moreover, concepts such as BI concentrating solar systems could also be examined provided that the system is viable from technical/economic point of view.

In the German national research and development project “HeizSolar” the building concept of Solar-Active-Housesis analyzed. The concept allows for a high fraction of solar thermal energyof more than 50% of the total heat supply. Within the project nine existing buildings have been monitored since the beginning of the heating period of 2011. The technology applied for this kind of supply concept has been introduced in [1,2]. Based on the data obtained from the in-situ monitoring, typical operation conditions have been identified and analyzed in [3]. The measured datawas also used to derive parameters to calibratea dynamic system simulation model for Solar-Active-Houses[4]. Theelaborated model focuses on the performance of the solar thermal collector as well as the solar circuit. What is more, the dynamic interaction between the solar thermal heat generator and the auxiliary heating systems as well as the heat distribution system are incorporated in detail. Finally the diffuse heat flux resulting of the integration of large hot water storage tanks into the building envelope is implemented to the model. This model is applied in the following to analyze the general thermal behavior of the supply concept and to derive optimization potentials. In detail the systems performance in regard to different types of heat transferal systems for space heating is demonstrated. Also the dimensioning in regard to the key parameters of collector area and the thermal capacity of the storage system consisting of a hot water storage tankare stated.

The paper presents investigations on the process performance of different membranes with and without backing structure in direct contact membrane distillation. Influences of backing structures and their orientation are identified. An integrated membrane and backing model was developed. Laminates with different backing designs were examined over a wide range of operating conditions and compared to results for the same membranes without backing. Experimental results and model predictions for flux and thermal efficiency are compared. The model predictions agree well with the experimental results. An influence on the effective area for diffusion, an increase in effective diffusion path length in the membrane and the formation of a complex network of thermal resistances are considered to be the main effects, leading to a significant reduction in process performance due to backing structures. The backing was identified to be one of the key components for further improvement in MD applications. An integrated assessment of membrane properties in combination with backing structures was carried out by analysing membranes with different thicknesses and different pore sizes. The experimental observations show good agreement with theoretical considerations. A combined analysis of specific flux and thermal efficiency leads to comprehensive understanding of the process and its potential for optimisation.

A new multi-channel spiral-wound membrane distillation (MD) module with a membrane surface area of 27.5 m 2 was developed, constructed and characterized. For comparison, a set of different conventional single-channel direct contact membrane distillation (DCMD) module prototypes is introduced and experimentally evaluated, as well. Furthermore, a comprehensive assessment on DCMD module design and operation as well as methods for comparative thermodynamic MD module evaluation has been conducted. The methodical core of this work specifically addresses an integrative method for the derivation of the thermal energy demand of DCMD systems, comprising specifications of the external heat recovery system. A new strategy for the optimization of energy demand in DCMD is identified, which aims on the formation of parallel temperature profiles by adjusting the flow streams on the evaporator and the condenser channel. Suitable methods for a comparative analysis of different MD performance results are suggested and fundamental MD specifications are derived and applied to evaluate a set of different DCMD prototypes. The methods involve the analysis of the permeate output rate, flux and thermal energy consumption with respect to feed flow rate conditions. The optimization of flux and thermal energy consumption is identified to rely on conflicting requirements, which cannot be satisfied at the same time. The optimal combination of flux and thermal energy consumption depends on the projected scenario and may not be identified by a technical assessment alone. Economic considerations must be included. As final outcome, a method of specifying MD results by a representation of flux versus thermal energy consumption is suggested in order to allow a meaningful evaluation and to achieve global comparability among different MD configurations and other thermal separation technologies.

The influence of mixed maritime atmosphere on the degradation of metallic components of exposed solar thermal collectors was studied. Corrosion measurements of standard metal samples (unalloyed carbon steel, zinc, copper and aluminum) were performed according to ISO 9226/1992 and ISO 9223/2012 with two different test set-ups; one in the open atmosphere, the other inside a commercial flat-plate thermal collector. Moreover, the influence of defined microclimatic conditions inside the thermal collector on the durability of different absorber surfaces was investigated. The results show extremely high corrosion rates in the open atmosphere for all exposed metals in contrast to the samples inside the solar thermal collector, where high corrosivity was only detected for amorphous metals. The results of optical measurements of the exposed absorber samples show a very good stability of the materials. Additionally, different analytical methods were used for the characterization of corrosion products. This information can be used for the optimization of accelerated aging tests for absorber materials with respect to corrosive environment and salt content.

Photovoltaic–thermal (PVT) collectors are hybrid collectors which make, in principle, optimal use of the solar resource by co-generating electricity and heat in a single module. Spectrally selective but transparent low-emissivity (low-e) coatings are a suitable measure to reduce thermal losses. In this paper the development of PVT collectors with low-e coatings by means of experiment and simulation is presented. A highly transparent low-e coating based on silver, specifically optimized for the application in PVT collectors, is developed. By combining layers of low-refractive SiO2 and high-refractive TiO2 a low emissivity of ɛ373K = 0.13 is achieved while maintaining high solar transmittance of τAM1.5 = 0.79. This coating is applied in a glazed, flat plate, liquid-type PVT collector. Thermal and electrical performance were tested and compared to a PVT collector with the same design yet without low-e coating. A numerical model of the PVT collector is presented showing good agreement of simulation and experiment. With this model the impact of low-e coatings on thermal and electrical performance is analysed and discussed. The newly developed low-e coating reduces the collector heat losses by 82% while the electrical efficiency drops by only 3%.

The water supply of many countries in the Middle East relies mainly on water desalination. In Qatar, the water network is completely fed with water from desalination plants. One of these power and desalination plants is located in Ras Abu Fontas, 20 km south of the capital Doha. The heat required for thermal desalination is provided by steam which is generated in waste heat recovery boilers (HRB) connected to gas turbines. Additionally, gas fired boilers or auxiliary firing in the HRBs are used in order to decouple the water generation from the electricity generation. In Ras Abu Fontas some auxiliary boilers run 24/7 because the HRB capacity does not match the demand of the desalination units. This paper contains the techno-economic analysis of two large-scale commercial solar field options, which could reduce the fuel consumption significantly. Both options employ parabolic trough technology with a nominal saturated steam output of 350 t/h at 15 bar (198°C, 240 MW). The first option uses direct steam generation without storage while the second relies on common thermal oil in combination with a molten salt thermal storage with 6 hours full-load capacity. The economic benefit of the integration of solar power depends mainly on the cost of the fossil alternative, and thus the price (respectively opportunity costs) of natural gas. At a natural gas price of 8 US-$/MMBtu the internal rate of return on equity (IRR) is expected at about 5%.

Hybrid photovoltaic-thermal (PVT) collectors co-generate solar electricity and heat in a single component with an optimum utilization of space. Spectrally selective but transparent low-emissivity (low-e) coatings are a proven method to reduce thermal losses. However, overheating and stagnation are critical issues for these collectors due to material degradation, thermal stress, and low electrical efficiency. This paper presents a PVT collector concept with variable film insulation as overheating protection. An inflatable glass-film cushion regulates thermal losses. Performance and stagnation tests were carried out with a prototype. During normal operation the collector achieves a high thermal efficiency. In periods of standstill, the deflated cushion has a high heat dissipation rate by deactivating the low-e coating. Stagnation temperatures are thus limited to 95 C. To conclude, the PVT collector combines the advantages of glazed and unglazed PVT collectors which are a high thermal efficiency and low stagnation temperatures.

The European Union (EU) and the Hashemite Kingdom of Jordan are executing a project “Capacity Building for Wind Energy and Concentrating Solar Power in Jordan – WECSP”, financed by the EU under the ENPI and EuropeAid Program. Beneficiary is the National Energy Research Center NERC, Amman, Jordan. Within this project, testing facilities and pilot plants for both wind energy and concentrating solar power (CSP) will be established at a site owned by NERC. To support NERC, a Technical Assistance (TA) team led by the Fraunhofer Institute for Solar Energy Systems ISE has been contracted. We report on the execution of the TA contract and the resulting implementation of the WECSP project so far, including the legal framework and preparations for CSP installations in Jordan, requirements, grid connection, power purchase and experiences made. The assessment of solar resources at different sites as one main criterion in the site selection process is reported, including the actual resource information for the chosen site at Al Fujeij. The preparation of technical specifications for the CSP tender is reported, containing the CSP pilot plant the CSP test lab equipment. We describe the resulting tender and the evaluation procedure of the six bids that had been received. A supply contract was signed between the owner of the plant NERC and the technology provider Solar Euromed for the supply of a CSP pilot plant of 0.5 MWe capacity based on Linear Fresnel collector technology, the delivery of test equipment and training and capacity building activities. The pilot plant and test lab will be implemented during 2014/2015. Details on the actual status of implementation will be presented elsewhere.

The present work aims at the experimental evaluation of the kinetic performance achievable by an innovative binder-based coating developed for application in adsorption chillers or heat pumps. It employs a commercial SAPO 34 as adsorbent material and a clay as binder. Samples with different thickness were prepared at the CNR-ITAE labs and their adsorption kinetics has been tested with a volumetric apparatus based on the Large Pressure Jump (LPJ) approach, available at the Fraunhofer ISE labs. For comparison purposes, also two representative loose adsorbent grain configurations, namely monolayer and multilayer, have been tested. The experimental evolutions have been fitted by means of a heat and mass transfer model, which allowed the determination of the effective diffusion coefficients and the effective heat conductivity as a function of the thickness of the samples. The effective diffusion coefficients showed a linear increase with the square of the coating thickness, which demonstrates that mass transfer is mainly limited by diffusion inside adsorbent grains. Finally, employing the obtained effective parameters, half-cycle simulations (adsorption after temperature jump) in real operating conditions of an adsorption chiller have been carried out for the tested adsorber configurations. A coating thickness of 0.6 mm was identified to be the most promising in terms of achievable Volumetric Specific Cooling Power (VSCP).

International audience; Photovoltaic-thermal (PVT) hybrid collectors are co-generation components that convert solar energy into both electricity and heat and represent in principle one of the most efficient ways to use solar energy. The aim of the study presented in this paper is to assess the performance of this type of collector as part of a solar thermal system. First of all, the development and the test results of an experimental flat plate PVT collector are described. Then, in the second part, the performance of this hybrid collector being part of a solar thermal system in a building is determined and compared to that of systems operating with standard solar devices (i.e. solar thermal collector and PV panel), through simulations using TRNSYS. Comparisons according to various evaluation criteria were made assuming the same surface area and under the same climatic conditions. The results show that in configuration of limited available space for solar collector area, the use of efficient PVT collectors in the building envelop can be more advantageous than standard PV and solar thermal components, not only from an energetic point of view, but also considering the exergy and the primary energy saving.

New facades of high-rise buildings often include renewable energy converters to allow "green building" operation. At the same time, numerous tenants value visual transparency. Transparent solar thermal collectors (TSTCs) aim at decreasing the non-renewable primary energy demand and increasing the visual transparency at the same time. On the one hand, this paper presents the main modelling challenges that arise when considering building facades and especially integrated TSTC systems. New transient systems simulation (TRNSYS) [Beckman, W. A., L. Broman, A. Fiksel, S. A. Klein, E. Lindberg, M. Schuler, and J. Thornton. 1994. "TRNSYS The Most Complete Solar Energy System Modelling and Simulation Software." Renewable Energy 5 (1-4): 486-488] types have been especially developed for this purpose. A simplified model is presented for comparison purposes. On the other hand, the overall performance for a building with facade-integrated TSTC, as measured by its non-renewable prima ry energy demand, is treated. This is achieved by considering a complete simulation model coupling the TSTC, building and heating, ventilation and air conditioning operation. Possibilities for primary energy savings are investigated using the building mass as additional thermal storage.

The development of small to medium size, autonomous and robust desalination units is needed to establish an independent water supply in remote areas. This is the motivation for research on alternative desalination processes. Membrane distillation (MD) seems to meet the specific requirements very well. This work is focused on experimental studies on full scale demonstration systems, utilizing a parallel multi MD-module setup. Three different plant concepts are introduced, one of them is waste heat driven and two of them are powered by solar thermal collectors. Design parameters and system design are presented. After the analysis of plant operation a comparison among the plants as well as a comparison with laboratory experiments is carried out and discussed. Impact of different feed flow rates, salinities, operating hours and process temperatures are taken into consideration and put into relation. GOR values and specific thermal heat demand are derived and compared. Energy balances of all three plants are given, uncovering heat losses and identifying room for improvement.

Transparent facade collectors can provide solar heating and cooling and lead to primary energy savings even compared to an opaque wall. They can be simulated with a detailed physical model based on laboratory measurements. The demonstration installation in Ljubljana will provide extensive measurement data of transparent facade collectors in an outdoor environment. This allows a comparison with simulations performed with the model validated by laboratory measurements. This paper presents the demonstration installation and the measurement system, which are based on the new modelling abilities and focused on the outdoor validation of such models.