The technologies have been chosen based on their cost effectiveness, energy use and generation efficiency, reliability and applicability in a wide range of building types. End user will be empowered to take an informed decision regarding the renovation extent followed by principles of Integrated Project Delivery (IPD) leading to the final selection of the technologies to be installed. At least five of the ReCO2ST components will be required to ensure the advantages provided by the method (Hard Constraints). There is however choice in terms of model, system, technology etc.

Cool Roofs and Pavements are designed to reflect more sunlight and absorb less heat than a standard roof and pavement. Cool Roofs and Pavements are identified as components that are able to deliver high solar reflectance and high thermal emittance. They reduce heat load for air conditioning system, energy usage and CO₂ released to the atmosphere. Cool Roofs can be made of a highly reflective type of paint, a sheet covering, highly reflective tiles or shingles. Standard roofs can reach temperatures of 65°C or more in the summer. A cool roof under the same conditions could stay more than 10°C cooler. The same applies for Cool Pavements

In the ReCO2ST project, cool materials will be exploited for residential applications and microclimatic interventions. Research shows that CO₂ emissions can be reduced by 1.9 to 7.5 kg/m² of cool roof area. Furthermore, the urban heat island effect can be mitigated through cool materials by reducing air temperatures at city scale by 1-2°C on average, as less heat transfer from a cooler surface to the ambient air. Moreover permanently retrofitting urban roofs and pavements in the tropical and temperate regions of the world with solar-reflective materials would have an equivalent effect on global temperatures as inhibiting the emissions of 44 billion tonnes of CO₂, or over one year’s worth of humanity’s CO₂ emissions.

In cooling dominating regions a typical retrofitting solution is the installation of a ventilated façade. This ventilated façade can include a certain thickness of insulation and in this way it becomes an appropriate solution for both winter and summer. Nevertheless, the potential of this technique for summer condition is insufficient if we want to ensure a significant reduction of the cooling needs. For this purpose, or even to avoid any energy consumption for space cooling, the ventilated façade has to provide cooling evaporative effect. The operation modes of a technology that has been proved in test cells by the Thermal Engineering Group of UCA. Experimental campaigns in test cells have shown up to 70% of energy savings for space cooling, and for summer warm climates like the Mediterranean coast, this technology can avoid any energy consumption for air-conditioning. The potential of this technology increases with the ratio CEVF area to gross floor area, and for this reason, it should be used as much to exterior surfaces and roofs as possible.

The Intelligent Energy Management System (IEMS) is a supervisory controller that optimizes trade-off between indoor air quality (IAQ), energy and comfort, adapting to climate conditions and user preferences. IEMS implements an automatic on-line closed-loop control algorithm that acts on component schedules and set-points in real-time. Selected sensor reading and IEMS decisions are displayed on a user interface (GUI) to increase user awareness on energy, IAQ and environmental impacts. In addition, the GUI is interactive allowing the user to select preferences and view predictions on potential savings thanks to the learning module of the IEMS.

UTRCI has developed a methodology and a physics-based decision support tool to evaluate the effects of different ventilation solutions on key performance indicators. A catalogue of ventilation systems, commercially available as well as newly designed by UTRCI, were simulated and the best performing systems were identified and recommended for each demo site building. Selection criteria is to maximize thermal comfort and indoor air quality at a lower cost, a minimal energy consumption and a lower environmental impact. These include a mechanical demand control ventilation system which incorporates phase change materials, which is installed in the UK demo site for further testing. An innovative air handling unit (IAHU) system designed, in collaboration with CARRIER company and UCA, incorporating the benefits of heat recovery and direct and indirect evaporative cooling, was recommended for Cadiz demo site and is currently in the process towards installation. In addition to the IAHU, the HVAC system for Cadiz also includes an efficient heat pump working as an auxiliary system for domestic hot water production to complement solar thermal panels.

As specialists in the nature-based solutions, alchemia-nova has developed two automatable bio-technical indoor air-treatment systems for inclusion in the Retrofit-Kit. The systems are based on the air purification, cooling and humidification properties of specially selected plants. They improve indoor air quality and thermal comfort by filtering out harmful Volatile Organic Compounds (VOCs) and Particulate Matter (PM), and by regulating relative humidity levels, enhancing also significantly the aesthetics of the indoor environment. The first comprises of a decentralised pot-plant-based system (AeroPlant) easily installed into buildings as part of a retrofit-kit, or as stand-alone solutions. The second system (Casetta) is a semi-centralised unit that can be installed in a window, in which ambient-air is treated by directing ventilation through a “winter garden”-like plant chamber.

Energy Harvesting: “Innovative solar photovoltaic (PV) systems comprising three optical concentrators, ACPC, CPC and V-Trough, have been designed through a rigorous computer-modelling, sized and manufactured by Brunel University London team. Designs take into account local solar and ambient conditions to achieve highest possible optical efficiencies and maximum power outputs. Prototypes have been already installed at London (UK) and Vevey (Switzerland) demo-sites and will be soon installed at Cadiz (Spain). Panels are equipped with instrumentation and monitoring systems facilitating power, temperature and radiation data on a 15 minute basis. Measured data is being used to validate the computer models and predict payback periods and reduced carbon emissions for each demo-site in a range of deployment scenarios.

A smart window solution will be implemented in the renovation concept. The Smart window is based on a solution developed in the EU CLIMAWIN project. This solution included triple plane glazing, integrated solar shading, preheating of ventilation air and wireless room zone control for IEQ optimization. This solution was developed for renovation projects, where comfortable controlled ventilation is required, but installation of a balanced mechanical system is difficult or very expensive. In the ReCO2ST project the idea is to further develop this smart window technology by optimising harvesting of solar energy (thermal) and heat recovery. The existing smart window will be combined with an air based solar thermal collector (installed in combination with the window), a PCM solar energy storage, an air to water heat pump on exhaust air and an intelligent control solution to optimise solar energy harvesting, energy storage and exhaust air heat recovery. The solution will also include a night cooling option to improve summer comfort.

VIPs – or vacuum insulation panels – are flat panels for optimised temperature insulation that are based on the principle of the thermos flask. These panels offer unparalleled heat insulation at minimum thickness. Conventional insulation (EPS, glass wool, PUR) layers cannot be adopted in all buildings, especially those existing buildings which are compact, are located in the dense town areas and/or are listed (conserved) for historical or cultural reasons. In such cases VIPs are the best option considering that an up to 7 times thinner section of VIPs can deliver the required low U-values. Motivation to insulate wall and floor surfaces with VIPs is dictated by fuel savings, indoor comfort improvement, and indoor space savings requiring minimal interruption to existing building design and structure. The shown value for VIP of 0.007 W/(m∙K) is the overall value for thermal calculation in buildings, including heat bridges at the edges and aging effects due to air and water vapour intake estimated over a period of 25 years in use. The RECO2ST project aims to overcome current cost, weight and durability drawbacks of commercially available VIPs by presenting a new revolutionary generation of VIPs. The new VIPs will be based on world’s first CO2 blown open pore nanostructured foam core. ReCO2ST is thoroughly optimising and characterising the foam and its use as core material for VIPs. A thermal conductivity of less than 5 mW/(m∙K) has been achieved, which is similar to conventional VIPs. The ongoing project will deliver additional knowledge in science and characterization of micro-structured organic foams, vacuum insulation materials, large scale industrial production of VIPs.