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In a previous paper, we have introduced a simulation and optimization framework for the integration of renewable generators into an electrical distribution network. The framework searches for the optimal size and location of the distributed renewable generation units (DG). Uncertainties in renewable resources availability, components failure and repair events, loads and grid power supply are incorporated. A Monte Carlo simulation–optimal power flow (MCS–OPF) computational model is used to generate scenarios of the uncertain variables and evaluate the network electric performance with respect to the expected value of the global cost ( ECG ). The framework is quite general and complete, but at the expenses of large computational times for the analysis of real systems. In this respect, the work of the present paper addresses the issue and introduces a purposely tailored, original technique for reducing the computational efforts of the analysis. The originality of the proposed approach lies in the development of a new search engine for performing the minimization of the ECG , which embeds hierarchical clustering analysis (HCA) within a differential evolution (DE) search scheme to identify groups of similar individuals in the DE population and, then, ECG is calculated for selected representative individuals of the groups only, thus reducing the number of objective function evaluations. For exemplification, the framework is applied to a distribution network derived from the IEEE 13 nodes test feeder. The results show that the newly proposed hierarchical clustering differential evolution (HCDE) MCS–OPF framework is effective in finding optimal DG-integrated network configurations with reduced computational efforts. [ABSTRACT FROM AUTHOR]

Building renovation is too often carried out with only one objective: necessary maintenance, updating design and functions, or reducing energy consumption. But, if a necessary maintenance is exploited as an opportunity for renovation, energy improvements can be implemented, house functions can be updated, and indoor climate improved with minimal nuisance and expense. This paper illustrates this approach by documenting the renovation of a single-family house in Denmark, and monitoring its energy consumption and indoor climate before and after the renovation. Building elements were replaced where necessary, and the total energy consumption was reduced by 23%, giving the house owners a saving of about DKK 8400 per year. The energy consumption for heating was reduced by 53%, close to the 58% found using dynamic simulations. The temperatures reached a more comfortable level, and the house owners were satisfied with the result. The increased value of the house was estimated to cover about 77% of the investment. [ABSTRACT FROM AUTHOR]

The Boosted MED technology is a thermal desalination process dedicated to low-grade waste heat sources. By augmenting the standard Multi Effect Distillation (MED) process with an additional Booster Module, the system is capable of further exploiting the heating medium output stream of the basic MED system and boosting the freshwater production of the system in an effective manner. This paper experimentally evaluates the principal design basis of the Boosted MED technology. A state-of-the-art pilot plant consisting of two evaporator modules in a serial connection is used to assess the additional vapour production from the downstream evaporator, which adequately mimics the booster unit, at heat source temperatures of 68 °C to 93 °C, cooling water temperatures of 20 °C to 35 °C, and two feedwater salinities. Additional vapour production rates ranging from 33% to 57% at sufficiently high temperatures demonstrate the general viability of the design hypothesis. The stable operation and the very high distillate quality achieved by the pilot plant augur well a favourable system characteristic. The process simulation model developed for designing and optimising Multi Effect Distillation based technologies has been experimentally demonstrated to be consistent with the pilot plant performance. [ABSTRACT FROM AUTHOR]

Performance simulation applications require reliable information regarding the intensity of solar irradiance on arbitrarily oriented building surfaces in order to properly predict buildings' energy use or to configure building-integrated solar energy systems. Since measured irradiance databases typically include only horizontal irradiance values, solar radiation intensity on inclined surfaces must be computationally derived. In this context, the present paper compares six options to derive, from horizontal irradiance data, solar radiation intensity levels on inclined surfaces. To evaluate these options, simulated downward vertical irradiance on four orientations were compared with measurements obtained in Austria. Two options that use both global and diffuse horizontal irradiance values for sky radiance generation delivered slightly better results than the others, which require only global horizontal irradiance. However, the range of errors was rather high for all options. Even for the best-ranked option, no more than 64% of the results had a relative error of less than ±20%. [ABSTRACT FROM AUTHOR]

• Real prototype of a solar thermal plant (STP) is developing. • Different sensor measurements are made. • A simulation model of the thermal power plant was created. • Matching between prototype and simulation model. A solar thermal plant (STP) is a renewable energy source that converts heat from the sun into electricity through the chimney effect. Its main components are the chimney tower, ensuring a temperature gradient, and the collector area, converting the sun radiation into heat. The amount of electricity produced depends on the chimney dimensions, the collector area and the properties of the absorbing materials, and the respective efficiencies of the mechanical turbine and electrical generator transforming the air flow kinetic energy into electrical energy. The paper presents a specialized computer model for simulating a solar thermal plant (STP). An experimental prototype is also designed and constructed, which is provided with various sensors (optical, temperature, barometric). The prototype's parameters and the experimental data acquired by the sensors are used as input to the computer simulations. A comparison is made of the simulated and the actual characteristics of the STP and conclusions are drawn concerning the STP design in view of its efficient operation under various weather conditions. [ABSTRACT FROM AUTHOR]