This project aims at contributing to the enforcement of the requirements of Directive 2012/27/ EU of the European Parliament and of the Council on energy efficiency in the temperate climate zone, including Latvia, providing the construction of nearly-zero energy buildings (nZEB) from 2019. For economically justifiable mass construction with regard to nearly-zero energy buildings (nZEB) systemic solutions are required - smart technologies and software for management of the building systems need to be developed alongside industrially manufactured, lightweight and adaptive structures and a minimised labour-intensity of the assembly on-site.

In this non-business project in cooperation with Riga Technical University (RTU) industrial researches will be carried out in order to develop the sustainable solutions of the building envelopes based mainly on the cellular wood structures with an integrated network of microcapillary heat exchangers for buildings’ heating and cooling using renewable energy resources: a ground–water heat pump and heat recovery in the ventilated facade and through the ground. In order to minimise the energy consumption needed for set indoor thermal comfort under conditions with a rapidly changing solar radiation and great diurnal temperature variation, both passive solutions, including the use of phase change materials (PCM) and the remote management software based on the measurements of the built-in sensors with the operational weather forecast will be developed.

The analysis of selected solutions with local and high-tech materials (e.g. aerogels) will be made using the multiphysical modelling of mass and heat transfer processes. Prospective materials and system's elements will be tested in different ways under laboratory conditions; and the complex in-situ testing concerning the efficiency of the management software, and the optimized building constructive solutions will be performed under real climate conditions in the experimental buildings creating the nZEB prototype therein. The project outcomes - functional models, testing and monitoring data and analysis of numerical modelling results will establish a knowledge database for an economically justifiable and sustainable implementation of the lightweight, adaptive industrial building structures and adequate building management systems to provide indoor thermal comfort and effective use of renewable resources appropriate to specific climate conditions.

This research and development project (NACE 72.19 and 41.10) is intended to be implemented from 1 April 2017 to 31 March 2020.

Keywords: nearly zero energy buildings, adaptive materials, smart technologies, functional models, climate conditions.

The overall objective of the project is to contribute to the enforcement of the requirements of Directive 2012/27/ EU of the European Parliament and of the Council on energy efficiency in the temperate climate zone, including Latvia, creating know-how necessary for that purpose. The specific objective of the project is the development of the complex solutions based on the smart materials, innovative technologies and renewable resources for the nearly zero energy buildings (nZEB), the optimization and testing of their energy efficiency and sustainability by creating an experimental prototype and performing its monitoring under real climate conditions. This is necessary because, in accordance with that Directive, an economically justifiable mass construction with regard to nZEB should be started in 2019. Thus this study corresponds to the priorities "Smart materials, technologies and technical systems" and "Smart energy".

In this non-business oriented project the systemic solutions will be made - smart technologies and software for the energy efficient management of buildings´ heating, cooling, ventilation systems and optimal indoor thermal comfort need to be developed alongside industrially manufactured, lightweight and adaptive building structures and a minimised labour-intensity of the assembly on-site.

The specific objective of the project is the development of know-how concerning an energy efficient and sustainable construction under the temperate climatic conditions (also in Latvia). For reaching it the proposed complex approach of this project including such aspects as materials, the constructive solutions, the building systems, the management software etc., on the one hand, and functional models for numerical modelling and prototype, on the other hand, is essential. The attendant objective of the development is to facilitate the use of economically justifiable local materials (e.g. wood pellets, chips and similar products) and the use of renewable energy resources (e.g. heat pumps) which are important for the development of the Latvian economy.

The established a publicly available know-how database will provide the possibility for the construction companies to choose options of the adequate, energy efficient and experimentally tested solutions for building technologies and appropriate systems for specific projects.

Directive 2012/27/ EU of the European Parliament and of the Council on energy efficiency determines the significant requirements concerning a reduction in the consumption of energy in the building construction sectors, including construction of nearly-zero energy buildings (nZEB) from 2019. Greenhouse gas emissions and related global warming processes are topical challenge facing the world; the construction branch has a very important role in solving this issue because in certain countries (also in Latvia) it determines in fact more than half of the total energy consumption.  In Northern Europe dominates the energy consumption for heating, in southern Europe - for cooling, while in the European temperate climatic zone (incl. Latvia) with a great diurnal temperature variation and high relative air humidity the complex and optimally controlled solutions for heating, ventilation and cooling are required in order to ensure category A of thermal comfort conditions and quality of life. In such circumstances, the required “peak” capacity and the total energy consumption are notably influenced by the choice of the construction materials and the building constructive solutions, so the dilemma arises between their impact on energy efficiency, sustainability and the total life-cycle costs.

Therefore, in addition to high-tech materials and structures the use of effective local materials, locally available renewable energy resources and various passive technologies are of great importance for economy. Taking into account the above mentioned the optimal solutions are only possible based on systemic approach to addressing the challenges of existing complex energy efficiency, thermal comfort and sustainability. It is therefore necessary to combine the complementary approaches of process research including the testing in-situ and under laboratory conditions, numerical heat transfer modelling, estimation of indoor thermal comfort conditions, analysis of total life-cycle costs of the complex solutions and the long-term monitoring under real climate conditions.

Such necessity is determined by the fact that the properties of structures are changing during operations both immediately after their construction and over the long-term process of ageing. Thus, the outcomes of the calculations and laboratory testing, as shown by previous research experience, may differ considerably from the actual physical properties when operating structures and building systems under real climate conditions.

It is essential to note, that there is no experimental testing ground in the temperate climatic zone similar to one, which is constructed at the UL. The various measuring equipment for required laboratory measurements an appropriate mathematical modelling software base (ANSYS, HeatMod etc.) are also accessible to the project partners for further developments. The highly qualified personnel provide assurance that the project objectives will be achieved qualitatively within the planned time-frame.

In order to effectively address existing challenges of this project within the complex approach, the main attention focuses on the least studied factors for the temperate climatic zone incl. Latvia:

 sustainable materials with the adaptive thermal and humidity properties;

 lightweight local materials, including different wood products and pellets;

 energy efficient constructive solutions with a high degree of integration and industrial preparedness;

 appropriate solutions for the use of renewable resources, including heat pumps;

 sustainable passive solutions to ensure thermal comfort with reduced energy consumption;

 high-precision functional models and software for the prediction of the energy consumption and the thermal comfort conditions concerning nZEBs;

 user-friendly software for the building management systems, using the measurements of the built-in sensors and an operational meteorological forecast.

 the creation of the nZEB prototype and the long-term monitoring under real climate conditions.

Thus, a set of obtained knowledge not only directly improves the competence of researchers involved and the quality of education and training at the UL and RTU in a particular field, but also will be available and useful for all persons involved in the construction branch in order to enable them to choose energy efficient, thoroughly verified and sustainable solutions.

The direct target group of the project includes researchers, PhD students and students working in the fields of engineering science, applied physics and environmental sciences, whose competence by involving them in the project activities will be purposefully developed in the research fields such as energy efficiency and sustainability, as well as the quality of life.  This target group is determined by the interdisciplinary nature of the research to be performed. Thus, by improving the competence of personnel and the practical experience as a whole, capacities of both universities will be significantly increased concerning the development of researches with a practical applications, researches of thermally adaptive building materials, researches of smart measuring and management systems, the evaluation of building sustainability and environmental quality, as well as in training of applied physics' professionals at the UL and building engineers at the RTU. These professionals are of vital importance for the development of the Latvian industry.

The indirect target group and the users of the project outcomes are the Latvian companies from the building construction industry (both the producers of construction products, building systems and construction companies) which need knowledge about independently tested, constructive adaptive and intelligent nZEB systems solutions in order to ensure the practical enforcement of Directive 2012/27/ EU of the European Parliament and of the Council on energy efficiency in Latvia, as well as to enhance their competitiveness in Europe and in the world.

The developed know-how will be made available to all construction branch professionals. Thus, it will be also indirectly available for other experts involved into areas of building construction and building operation (building engineers, architects, construction project developers, energy auditors etc.). They will have access to verified information, independent from producers, regarding characteristics of up-to-date materials and technologies, efficient use, as well as the existing limitations.  The prototype created for a new technology nZEB with the use of renewable resources for heating, cooling and ventilation will be made available to the general public in the territory of the UL Botanic Garden and may be demonstrated to a wide audience.

Where as it necessary to ensure the construction of nZEB in EU (also in Latvia) from 2019, the beneficiaries in the future will be all the occupants of such buildings where solutions of lightweight structures, developed and tested, the building systems with the use of renewable resources and their management systems based on the operational meteorological forecast will be used.

New and improved solutions for the building constructions based on adaptive lightweight materials, recommendation for the climate-optimized usage of renewable energy sources for the heating, cooling and ventilation, as well as experimentally tested user-friendly smart building management system with built-in weather forecast module will be developed in the frame of this project. All the research results and created solutions will be extremely useful for nearly zero energy buildings (nZEB) [1] in temperate climate zone with a large diurnal temperature variation and high air humidity. Physical properties of the building materials and constructions, as well as building management for nZEBs built in such climate zone are more complex because of the important impact of dynamic heat and moisture transfer effects and planned integration of weather forecast module will have a significant effect on improvement of building’s energy efficiency. In addition, use of globally actual phase change materials (PCM) will be analysed during planned experiments.

This project promotes the fulfilment of the requirements of Directive 2012/27/ EU of the European Parliament and of the Council on energy efficiency temperate climate zone incl. Latvia, helping to ensure the efficiency and sustainability mandatory requirements for nZEB construction from 2019 for state-owned buildings and from 2012 for all newly constructed building  [3, 4].

The obtained results will have the global impact, because of developed, optimized and experimentally tested building solutions, smart usage of renewable energy and weather forecast-based building management system will promote the improvement of building’s energy efficiency and, therefore, the reduction CO2 emissions; thermal comfort and safety requirements will be ensured too. Therefore, the project will provide the significant contribution in field of global building physics science.

Building’s energy efficiency, heat pump operation and thermal comfort research study made in exist experimental buildings, which are built in frame of previous projects, are widely used not only for highly scientific publication, but also for dozens of popular publication in Latvian press and for many by the University of Latvia organized workshops for builders and wide audience [5]. In the same way, all the results, findings and suggestion get from this project will made public available in local press and other mass media, as well as key results and recommendations will be presented at specially organized informative events for construction sector’s professionals and architects, improving their knowledge and qualifications and helping to choose optimal solutions for nZEB construction, which will be required in the coming years.

The aim of the research project comply with the first economic transformation direction "Structural changes of production and export in the traditional sectors of the economy" and 3rd priority "Energy efficiency” from the Latvian smart specialization strategy RIS3 [6].

Multiphysical modelling of mass and heat transfer processes, dozens of laboratory and in-situ experiments, as well as creating the real nZEB prototype and analysis of the results makes closer links between universities involved in the project, contributing the exchange of complementary theoretical and practical knowledge. It will provide an opportunity for bachelor or master students to prepare their works based on projects’ findings and expand the spectrum of scientific services provided by the universities for industrial customers (e.g. testing of materials or BMS software modules using built nZEB prototype).

[1] http://bpie.eu/documents/BPIE/publications/LR_nZEB%20study.pdf
[2] R. Lamedica, S. Teodori, G. Carbone, E. Santini, An energy management software for smart buildings with V2G and BESS, Sustainable Cities and Society, Volume 19, 2015, pp. 173-183.
[3] http://www.nezeh.eu/assets/media/PDF/bpie_factsheetnzeb_definitions_across_europe115.pdf
[4] http://likumi.lv/doc.php?id=258322
[5] http://www.eem.lv
[6] http://www.izm.gov.lv/images/RIS3_Baltic_dimension_25032015.pdf

Directive 2012/27/ EU of the European Parliament and of the Council on energy efficiency determines the significant requirements for reduction of energy consumption in the buildings (the objective of saving 20% of the EU’s primary energy consumption), including the obligations or nearly-zero energy buildings (nZEB) construction. In Northern Europe dominates the energy consumption for heating, in southern Europe - for cooling, while in the temperate climatic zone with high relative air humidity (incl. Latvia) the energy consumption for both – heating and cooling is needed, especially in autumns and springs, when a great diurnal temperature variation exist. One of the solution for decreasing of energy consumption in buildings for this case is using of materials with high thermal capacity, which helps to reduce effect of short-term temperature "peaks" on heating and cooling load. Another possibility to reduce those "peaks" is smart controlled management solutions for heating, ventilation and cooling systems, which makes temperature control more effective by reducing unnecessary energy consumption, e.g. when heat amount is provided with the help of intensive solar radiation or there are no people in the premises and temperature be controlled no so precisely. The use of environment-friendly and sustainable raw materials for nZEB construction and usage of energy from renewable sources produced on-site or nearby is very important in terms of CO2 reduction for the whole building´s life cycle analysis.

The complex approach that will be used during the project includes such studies:

 Experimental research (incl. laboratory and in-situ measurements) of lightweight local materials and materials with the adaptive thermal and humidity properties;

 Analysis and numerical modelling of energy efficient constructive solutions with a high degree of integration and industrial maturity;

 Experimental research for the use of renewable resources in local climate, including heat pumps;

 Experimental research of sustainable passive solutions (e.g. ground ventilation system) to ensure thermal comfort with reduced energy consumption;

 User-friendly software development for the building management systems, using the measurements of the built-in sensors and an operational meteorological forecast;

 the creation of the nZEB prototype building

It is essential to note, that all in-situ measurements of physical properties of materials and constructions as well as energy efficiency monitoring of nZEB prototype building will be made at the same testing ground, where another test building exist, thus ensuring comparison with historical and real-time data from another experimental buildings

Planned scientific values of project are as follows:

 Experimental estimation of important thermophysical parameters of adaptive building materials and innovative building structures using laboratory and in-situ measurements; and analysis of their possible improvement;

 Developing and improvement of mathematical models and software modules used for energy efficiency calculations for nZEB;

 Developing and comprehensive testing of software for smart building management systems using an innovative solution – an operative meteorological forecast and buildings’ thermal inertia properties;

 Optimisation of complex solutions for nZEB in temperate zone climate with great diurnal temperature variation and high air humidity including materials, structures and building technologies;

 Approbation and monitoring of selected solutions in an erected nZEB prototype under real climate conditions.

Innovative level of planned nZEB research approach is determined by the fact that it is systematic, including:

 Complex analysis of the used materials and building constructions; study of impact of building management systems (heating, cooling and ventilation) on total energy consumption (energy efficiency); estimation of thermal comfort conditions in a room and buildings sustainability;

 A combination of thermophysical calculation, modelling of building energy balance and numerical estimation of thermal comfort conditions with the experimentally available measurements of properties for real materials and building structures, and verification using energy consumption data for a building which is operated under real climatic conditions.

Such a testing concept and opportunities under real climate conditions in temperate climate zone is unique.

The users of the project outcomes are the Latvian companies from the building construction industry (both the producers of construction products, building systems and construction companies) which need knowledge about independently tested, constructive adaptive and intelligent nZEB systems solutions in order to ensure the practical enforcement of Directive 2012/27/EU of the European Parliament and of the Council on energy efficiency in Latvia, as well as to enhance their competitiveness in Europe and in the world.

The project´s results and developed know-how will be made available to all construction branch professionals. Thus, it will be also available for other experts involved into areas of building construction and building operation (building engineers, architects, construction project developers, energy auditors etc.). They will have access to verified information, independent from producers, regarding characteristics of up-to-date materials and technologies, efficient use, as well as the existing limitations.

Results of research have direct positive impact to the RIS3 defined economic transformation direction "Structural changes of production and export in the traditional sectors of the economy", 3rd priority "Energy efficiency" and in the following sectors of national economy (NACE 2): "41. Construction of buildings" and "71. Architectural and engineering activities; technical testing and analysis".

A building management system or BMS (known also as building automation system, BAS), is a computer-based control system installed in buildings that controls and monitors the building’s mechanical and electrical equipment such as heating and cooling systems, ventilation, lighting, fire systems etc. Systems linked to a BMS typically represent 40% of a building´s energy usage; if lighting is included, this number approaches to 70%. BMS systems are a critical component to managing energy demand.

Some of the energy efficiency connected BMS benefits are:

 Control of internal thermal comfort, including possibility of individual control for separate rooms

 Effective monitoring and targeting of energy consumption

 Effective response to HVAC-related complaints

Taking into account factors, that effect the energy consumption or thermal comfort conditions in a building (e.g. presence of inhabitants, indoor air humidity, outside temperature, solar irradiation, wind properties) and following taking of some pre-defined automatic actions like switching off the lighting in the empty rooms, intensification of the ventilation in case of CO₂ increasing or reduction of heating power during sunshine hours allows to reduce energy consumption in the whole building while ensuring optimal comfort conditions. Described BMS system is extremely necessary for the buildings with low energy consumption (high performance buildings or nearly zero energy buildings).

One of the innovative ideas to be investigated, optimized, implemented and widely tested under real climate conditions in the frame of planned project using nZEB prototype is to integrate a weather forecast module into building management system, thereby modifying existing BMS into a smart BMS with prediction functionality. Operational (short-term) weather forecasting method, which is very accurate for short time periods, is planned to be used, because for the smart control of nZEB’s systems it is very important to have the very reliable and as accurately as possible information. The availability of weather data for the next hours will allow to smart control of following:

 reducing of heating system´s power when increasing of outside temperature and/or intensive sunshine is expected. Additional building´s data (e.g. heat capacity, internal heat sources) will be needed for the determination of exact reduction parameters;

 increasing of heating system´s power when decreasing of outside temperature is expected. Additional building´s data will be needed for the determination of exact reduction parameters;

 closing the outer window blinds when high wind speed is expected;

 other weather-dependent and with the help of BMS controllable parameters like lighting, air exchange etc.

The BMS’s software programs are usually configured in a hierarchical manner using such protocols as C-Bus, Profibus. Vendors are also producing BMSs that integrate using Internet protocols and open standards such as DeviceNet, SOAP, XML, BACnet, LonWorks and Modbus.

The use of BMS interfaces with the complete open protocol (e.g. KNX) is planned to be used for the planned development of nZEB prototype including weather forecast module, because of lower installation and operational costs, greater expandability, easier to manage. Such system is extremely flexible and is forward compatible with future building automation technologies. Very important factor is ability to remove, change or replace any part of the system with any other brand.

The thermal insulation materials and solutions of tomorrow have to satisfy several crucial requirements, for example, the proposed thermal conductivity requirement in the pristine condition is a conductivity less than 4 mW/(mK) and stability during their service life.

Vacuum insulation and Aerogels panels are most promising high performance thermal insulation materials for possible building applications. Only limited commercial products are available so far and their application in buildings is still limited.

Typical conductivity for non-aged vacuum insulation panels (VIPs) is less than 4 mW/(mK) and will be same after a certain period of time or service life, that is vital importance. VIPs can be subdivided into three categories: vacuum insulation panels (VIPs), vacuum insulating sandwiches (VISs) or sheet-encapsulated vacuum insulation panels and vacuum insulating glazing (VIG).

Gas-filled panels (GFP) are similar to VIPs. The GFPs apply a gas less thermal conductive than air, e.g. argon (Ar), krypton (Kr) and xenon (Xe), instead of vacuum as in the VIPs. To maintain the low-conductive gas concentration inside the GFPs and avoid air and moisture penetration into the GFPs are crucial to the thermal performance of these panels. Vacuum is a better thermal insulator than the various gases employed in the GFPs. On the other hand, the GFP grid structure does not have to withstand an inner vacuum as the VIPs. Low emissivity surfaces inside the GFPs decreases the radiative heat transfer. Thermal conductivities for prototype GFPs are quite high, e.g. 40 mW/(mK), although much lower theoretical values have been calculated. The GFPs have many of the VIPs advantages and disadvantages.

In the Nano insulation materials (NIM) the pore size within the material is decreased below a certain level, i.e. 40 nm or below for air, in order to achieve an overall thermal conductivity of less than 4 mW/(mK) in the pristine condition. The structure of NIMs is different from VIMs and GIMs, therefore prevention of air and moisture penetration into their pore structure during their service is needed.

Commercial Aerogels have thermal conductivity down to 13 mW/(m K) and they show remarkable characteristics compared to traditional thermal insulation materials. Also the possibility of high transmittances in the solar spectrum is of high interest for the construction sector. The high potential for aerogels may be especially found in its translucency and possible transparency, as the aerogels may provide large energy savings in future windows and skylights.

Phase change materials (PCM) are not really thermal insulation materials, but they are interesting for thermal energy storage applications in building. PCMs change phase from solid state to liquid when heated, thus absorbing energy in the endothermic process. Various paraffins are typically examples of PCMs, but their low thermal conductivity and a large volume change during phase transition limits their building application.

Materials based on natural fibres from renewable raw material resources are now becoming increasingly popular due to its low mass density and cell structure. They show very good sound and thermal insulation properties, often better and more advantageous than synthetic fibres. Another advantage is that it is a renewable material, which does not place any significant strain on the environment.