I. Visa*, A. Duta, S. Fota, C. Nastac

Transilvania University of Brasov, Centre: Product Design for Sustainable Development, Eroilor 29,

500036 Brasov, Romania

* Corresponding Author, visaion@unitbv. ro

Abstract

The concept of low energy building is mostly addressed to as an answer to the requirements for clean energy and environment protection. The use of renewable energy systems, implemented in the design of different residential applications must be correlated with the availability of the input energy and requires, in certain climatic conditions, supplementary co-generation systems. The integrated use of solar energy, for solar-thermal and solar PV conversion, along with a heating pump system, can offer an integrated solution for inner space and water heating/cooling and, partially, for the power consumption. The design of such a system must be adapted to the beneficiaries’ demands but, must follow a suitable, flexible algorithm. The paper presents the results obtained in the design of a combined system based on solar-thermal and heating pump system associated with a PV array, implemented in the building of the research department Product Design for Sustainable Development, in the Transilvania University of Brasov, Romania.

Keywords: Low energy building, photovoltaic, solar-thermal, heating pump

1. Introduction

The climatic changes due to the greenhouse gases (GHG) represent a major concern for our sustainable future. The eight Millennium Development Goals are the core of the meeting agenda in the next UN Session from 25 September 2008, when the world leaders are expected to renew their commitment and to set out concrete plans and actions, by 2015, for further sustainable development, including environmental sustainability. The concept answering to these needs involves sustainable energy: energy efficiency, energy saving and renewable energy systems, jointly approached both in economy sectors and at social/societal level.

European Community had clearly moved towards action for climate change mitigation, through reduction of GHG, sustainable development, security of supply and the development of a knowledge based economy, by developing the Directive on the promotion of the use of energy from renewable energy sources, [1]. The directive, known as 20/20/20 sets a mandatory target of a 20% share of renewable energies in overall Community energy consumption by 2020. The directive actually re­formulates the values of the targets previously set for each EU country thus long term plans can already be found, as it is the Dutch Future Energy System, [2] that considers a complex of actions for energy efficiency in industry, CO2 neutral feedstock for transportation, renewable energy and highly

insulated buildings in the built environment. The expected result is an 80% reduction of the GHG emissions (comparing with 1990), till 2050.

The long term strategies require an integrated approach, while resource management becomes a key issue; thus there must be considered the quantification of all the energy and materials needed in the consumption, both for construction/product development (embodied energy and materials) and for usage; exergetic life-cycle assessment models have been developed for approximating the overall needs in industrial but mainly in residential applications, [3].

Concluding, a reduction of the GHG emissions arising from the built environment can be achieved by the development of new building materials (with low thermal transfer coefficient) and the adoption of the building integrated renewable energy conversion technologies.