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The use of heat pumps in district heating is one of the most promising technologies for enhancing the efficiency of systems and for meeting the 2030 and 2050 European energy and climate targets. It is essential to assess the available data, the practice and experience of planners and engineers to determine heat pump placement, connection and operational modes in district heating networks, as the systems ought to be capable of covering residential heat requirements for all year around operation. The main selection criteria for the appropriate heat pump system are the heat source, the heat pump technology and the heat requirements. These parameters form a technical triangle, which should be used as a comprehensive instrument to enable heat pump integration into residential district heating. The triangle allows the definition of the bidirectional interdependences and the design of a high efficiency, sustainable heat pump based system. This paper presents the solution to scenarios of how to integrate heat pumps into district heating, in terms of heat pump placement, connection and operational modes based on available heat sources and heat requirement profiles and their environmental impact. [ABSTRACT FROM AUTHOR]

There is a considerable diversity of district heating (DH) technologies, components and interaction in EU countries. The trends and developments of DH are investigated in this paper. Research of four areas related to DH systems and their interaction with: fossil fuels, renewable energy (RE) sources, energy efficiency of the systems and the impact on the environment and the human health are described in the following content. The key conclusion obtained from this review is that the DH development requires more flexible energy systems with building automations, more significant contribution of RE sources, more dynamic prosumers׳ participation, and integration with mix fuel energy systems, as part of smart energy sustainable systems in smart cities. These are the main issues that Europe has to address in order to establish sustainable DH systems across its countries. [ABSTRACT FROM AUTHOR]

Purpose: To examine gay youth experiences within the context of normal adolescent development.Methods: Thematic analyses of interviews with 13 self-identified gay male youth, aged 16–22 years, each reporting minimal sexual identity distress, were completed. Interviews focused on: (a) descriptions of developmental changes perceived to occur for all adolescents, {b) descriptions of the participants'' developmental experience, and (c) participants'' direct comparisons of their perceptions of gay and nongay developmental experience. Data were analyzed by two investigators who, after initial review of the interview transcripts, developed a unified coding template to permit systematic analysis of the transcripts for recurrent themes.Results: (a) Few (2 of 13) participants reported overall developmental experience markedly different from nongay peers. (b) Peer interaction was seen as the domain most different from that of nongay peers. (c) Open gay self-identification altered, generally positively, all peer interaction. (d) Increased peer interaction enhanced maturity in other domains. (e) Family dynamics were not substantively altered by open gay self-identification. (f) Middle and high school were identified as relatively hostile environments in which to openly identify as gay, affecting the timing and the extent of self-disclosure. (g) Developmental progress showed asynchrony across developmental domains.Conclusion: General developmental dysfunction is not inevitable for gay adolescents, nor is identifiable personal or family pathology directly related to sexual identity. [Copyright &y& Elsevier]

Provides the abstract of the research titled 'More Normal Than Not: A Qualitative Assessment of the Developmental Experiences of Gay Youth,' which was presented at the annual meeting of the Society for Adolescent Medicine in Seattle, Washington on March 19-22, 2003.

Photovoltaic–thermal water collectors have the ability to convert solar energy into electricity and heat, simultaneously. Furthermore, the combination of photovoltaic–thermal solar collectors with a water cooling system can increase significantly the electrical and thermal efficiencies of the system, which can improve the total thermal efficiency of buildings. In this paper, the findings of six experimental configurations of solar-thermal collectors are presented and analyzed. Five of the solar-thermal panel configurations were implemented with a cooling cycle. Two of the solar-thermal panels were equipped with monocrystalline silicon modules, the other two collectors were equipped with polycrystalline silicone modules, one of the collectors was based on heat pipe technology and was equipped with a cooling system, while the last collector did not include any cooling cycle. The duration of the experiments was four days during the September of 2014 and they were conducted under different solar radiation conditions. The second part of the paper presents the simulation results for five of the solar-thermal panels connected with a cooling water tank (volume of 500 L), a domestic hot water tank (volume 350 L) and a water–water heat pump, in terms of covering the hot water demands of a single family dwelling. The results showed that the hybrid solar collectors would be able to cover approximately 60% of the dwelling's hot water needs for days with low levels of solar radiation, while for days with high solar radiation they could cover the hot water requirements of the family by 100%. [ABSTRACT FROM AUTHOR]

Provides the abstract of the research titled 'The Effect of Relationship Quality Change on Adolescent Condom Use Over Time,' which was presented at the annual meeting of the Society for Adolescent Medicine in Seattle, Washington on March 19-22, 2003.

Provides the abstract of the research titled 'The Effects of Relationship Quality on Adolescent Chlamydia Infection Over Time,' which was presented at the annual meeting of the Society for Adolescent Medicine in Seattle, Washington on March 19-22, 2003. Causal relationship between condom use and chlamydia infection.

The purpose of the paper is to investigate the challenges in modelling the energy losses of heating networks and to analyse the factors that influence them. The verification of the simulation was conducted on a test stand in-situ and based on the measurements of the testing station, a database for the final version of the numerical model was developed and a series of simulations were performed. Examples of the calculated results are shown in the graphs. The paper presents an innovative method of identify the energy losses of underground heating network pipelines and quantify the temperature distribution around them, in transient working conditions. The presented method makes use of numerical models and measured data of actual objects. The dimensions of the pipelines used were 6 m wide, 8 m high and 1 m in depth, while they were simulated under conditions of zero heat flow in the ground, in the perpendicular to the sides direction of the calculated area and considering the effects of ground's thermal conductivity. The mesh was developed using advanced functions, which resulted its high quality with the average orthogonal quality of 0.99 (close to 1.00) and Skewness of 0.05 (between 0.00 and 0.25). To achieve better accuracy of the simulation model, the initial conditions were determined based on the numerical results of a three-dimensional analysis of heat losses, in steady state conditions in a single moment. The validation process confirmed the high quality of the model, as the differences between the ground temperatures were approximately 0.1 °C. [ABSTRACT FROM AUTHOR]

A novel flat heat pipe design has been developed and utilised as a building envelope and thermal solar collector with and without (PV) bonded directly to its surface. The design of the new solar collector has been validated through full scale testing in Cardiff, UK where solar/thermal, uncooled PV and PV/T tests were carried out on three identical systems, simultaneously. The tests showed a solar/thermal energy conversion efficiency of around 64% for the collector with no PV and 50% for the system with the PV layer on it. The effect of cooling on the solar/electrical energy conversion efficiency was also investigated and an efficiency increase of about 15% was recorded for the cooled PV system due to the provided homogenous cooling. The new flat heat pipe solar collector is given the name “heat mat” and, in addition to being an efficient solar collector type, it is also designed to convert a building envelope materials to become energy-active. A full size roof that utilise this new building envelope material is reported in this paper to demonstrate the way this new collector is integrated as a building envelope material to form a roof. A thermal absorption test, in a controlled environment, from the ambient to the heat mat with no solar radiation is also reported. The test has proved the heat mat as an efficient thermal absorber from the ambient to the intermediate fluid that deliver the heat energy to the heat pump system. [ABSTRACT FROM AUTHOR]