Are Energy Efficient Retrofits as Good as Building New?

Monday, November 10th, 2014
liked this article
Autodesk – 300 X 250 (expire December 31)
goodshed north
FavoriteLoadingsave article

A new project is looking to develop a scalable, replicable, high energy efficient, zero emissions and cost-effective system to refurbish existing public-owned non-residential buildings to achieve a reduction in energy consumption of at least 50 per cent.

The BRICKER project, an energy efficient retrofits system, is being developed by combining passive and active technologies in live test cases of three very different public buildings situated in three different countries in three different climatic zones.

The three buildings being tackled are council offices in Extremadura, Spain; an engineering college building in Liege, Belgium; and part of a university hospital in Aydin, Turkey.

“What makes this project unique is it will combine different active and passive technologies to achieve energy efficiency, in an innovative way,” said project coordinator and mechanical engineer Juan Ramón de las Cuevas Jiménez. “The main breakthrough will stem from the development of an innovative tri-generation system for simultaneous generation of power, heating and cooling. Its power capacity will be around 150 kW and its thermal capacity, around 600 kW.”

“To produce the activation heat for this system, we will use roof mounted parabolic solar collectors, working on a higher-than-usual temperature, at about 250 to 270 °C. This system is already used in industry, but not yet for public buildings.”

In Spain, only active energy saving measures are going to be applied to the pilot building as it is relatively new and its passive behaviour with respect to energy saving is good enough. The project consists of integrating Parabolic Trough Solar Collectors (PTC), a biomass boiler, a heat and electricity cogeneration unit based on so-called Organic Rankine Cycle (ORC), an absorption chiller and a cooling tower.

goodshed north

The PTC and the biomass boiler will produce hot oil that will feed the ORC unit. The ORC unit will produce electricity as well as hot water. This water will be used for heating the building during winter. In summer, the hot water will go through the absorption chiller to produce chilled water to cool the building. The hot and chilled water will go to the terminal units that will condition the different building spaces.

“We are hoping to reduce the building’s energy consumption by about 50 per cent,” said Carolina Grau, general director of industry and energy at the Agriculture, Rural Development, Environment and Energy Council of the Government of Extremadura. “We then plan to use it as a showcase for the region to encourage the use of renewable energies, particularly solar and biomass.”

There are three main challenges to the project, said Noemí Jiménez, industrial engineer and director of the department of research and development of CEMOSA.

“The space restrictions due to the fact that it is an existing building; the control of the whole project components and their integration with the existing heating, ventilation, and air conditioning (HVAC) system; and the compatibility of the project goal of profitability of the building performance in the energy market with the Spanish regulations, which have restricted support for micro-generation from renewable energies,” Jiménez said.

In their more northerly clime, Belgian high-school building blocks will be upgraded to better hold onto energy; this will be done by insulating with a polyisocyanurate rigid foam (PIR) that contains “phase-changing materials.” These can absorb and store thermal energy which its structure changes.


“Simulations suggest that a five centimetre-thick PIR-insulation could reduce the thermal transmission factor ten-fold, and thus limit heat loss. After the reconditioning of the building, the walls and the roofs are expected to achieve a thermal transmission factor further cut by a third,” said Raymond Charlier, industrial engineering expert attached to the Liège Provincial Building Service.

The monolayer glass windows will also be replaced by double-glazing with built-in solar protective layer that is nearly four times more energy efficient. The frames will be executed in aluminium with a thermal bridge to limit heat losses. Above some window frames, a decentralised ventilation unit with heat exchanger will regulate the incoming flow of fresh air while the heat from the outgoing air flow will bring it up to temperature, increasing comfort and efficiency even further.

“It will diminish our electricity demand from the grid by 86 per cent and reduce gas consumption for heating in blocks one and six by 75 per cent, according to the preliminary estimations,” said Charlier.

In the Turkish showcase, the plan is to install solar films on east- and west-facing windows and solar shades on south-facing windows in summer to reduce the energy thirsty air-conditioning load.

In addition, they will install heat exchangers, allowing the incoming fresh cold air to be preheated by the outgoing stale heated air, without mixing each other. This helps to reduce the amount of natural gas consumed in the burners. The heat exchangers will work conversely in summers, cutting down the energy amount used for air-conditioning. Variable speed drives on fans and compressors will be incorporated to reduce the electrical energy used by the motors of these devices.

heat exchange

“After retrofitting, we expect to have the same comfort levels in the building, using 50% less energy,” said Yunus Çengel, dean of the faculty of engineering at the Adnan Menderes University in Aydin.

BRICKER Project co-ordinator Jimenez suggested that retrofitted buildings are potentially a better solution than building entirely new and more efficient buildings.

“We made calculations to prove that a 50 per cent reduction of energy consumption is possible with retrofitting, starting from old and non-efficient buildings. The investment levels in such measures are limited to about 20 per cent of the price to build a new similar building,” he said.

Energy consumption in the non-residential sector is typically around 40 per cent higher than in the residential sector in Europe. A major goal of the project is to refine its approaches so that they can be applied to other public buildings around Europe. The potential replication is one in 314 buildings in Belgium and Spain alone.

In Australia, governments collectively spend around $1 billion each year on energy and water. In 2011 the Energy Efficiency Council estimated that these Governments could typically reduce energy use and greenhouse gas emissions in their buildings by 25 per cent with an annual return on investment of seven to 15 per cent. Since then the Victorian Government, as an example, has been implementing energy efficiency projects it says will save $1 billion over 25 years.

A return on the European BRICKER retrofit research project is expected in around seven years.

FavoriteLoadingsave article


 characters available
*Please refer to our comment policy before submitting