Building systemsIn buildings where 40% of the total energy consumption is consumed, it is extremely important to ensure minimum energy consumption to achieve optimal living comfort and use of the building. By applying technical solutions to increase energy efficiency, buildings reduce energy consumption, but also increase the ease of living in space and the durability of the building. Choosing a solution depends on the energy status and type of building, the way its being used and the location, and would be ideally to use multiple solutions and link them to a unique whole system / system in order to achieve a greater savings effect through synergy of different solutions and smart management. Duplico d.o.o. took advantage of its long-standing experience and engineering knowledge and created a unique automated management system with various technical solutions aimed at increasing the energy efficiency of the building. The aforementioned system is implemented and tested on the new business premises of the company, which is fully built and equipped to achieve the highest level of energy efficiency. The awareness that energy consumption depends on the physical properties of the facility and the energy systems of heating, cooling, ventilation, electrical appliances and lighting which are used, quality materials are used during construction. According to the energy certificate, the object is classified in class B; QH, nd = 32.67 kWh / m2a.2a. From the above it is apparent that the facility was not built according to low energy standards but we tried to optimize the energy consumption by means of advanced automation systems by connecting low-temperature heating and cooling systems, LED lighting and solar power generation to 20 kW in a single management system to achieve what better results. All relevant energy systems are supervised and managed by SCADA system, designed and programmed by Duplico, in accordance with our M2e concept. This central control and monitoring system manages the fully automated processes of surface heating and cooling of buildings, production, consumption, delivery of electricity from their own solar powered and turning on and off lighting. Unique algorithms are required to operate the systems of different manufacturers in order to maximize the utilization of the energy consumed or needed.
Based on the long-standing cooperation with Weishaupt-Zagreb d.o.o., the entire system is integrated into the whole, using the company's equipment.. This enables integration of all applied energy systems into a common entity and greatly facilitates the management of the object. The system is based on open communication standards (BACnet IP, PROFIBUS FMS, LON, OPC, EIB), extending the choice of manufacturers of individual equipment and guaranteeing high adaptability in the event of a subsequent expansion. Displayed Neuberger's automated station for its modular concept provides adaptability in designing the system. Extensibility is achieved by additional modules freely programmed as a connection to the measurement technique and the executive units. Viewing the SCADA Home screen with the most important information on the state of heating and cooling and the production of electricity is shown in Image 2. Here is the status of the engine pumps and heat pumps, the data on measured temperatures in the system and the current power of the produced and consumed electricity are also visible. Each of the elements also has a detailed view of the management options and the display of measured sizes.
The heating and cooling of the building are carried out by the Variotherm system. The heating and cooling system management was performed with the aim of maximizing the utilization of solar power plant potential. The implemented program solution is based on the priority list. Using the available metering data actively regulates the heating and cooling level. Thus, in the heating mode, during the maximum utilization of the solar power plant, the heat energy is stored in the hot water tank while the cooling mode increases the cooling rate. Measurements of all temperatures in the system are available. All measured values are transmitted via the LON communication protocol to the Neuberger automatic station, which uses the advanced control algorithms to set the hot water temperature setting. Based on the measured values and the predicted heat energy needs, the correction of the heating curve is performed, which directly determines the water temperature in the heat insulated container. Here are algorithms based on fuzzy logic. By increasing the available electricity from a solar power plant, a higher water temperature in the tank is set to take advantage of current electrical conditions. Furthermore, based on the daily cycle of heating system regulation, in case of lack of electricity from its own production, the hot water tank is automatically heated in the period of lower tariff calculation of the purchased electricity, all in accordance with the current needs. Here comes the implementation of the entire heating system with SCADA system where the user chooses the periods in which the heating of the premises will be active. Thus, using the established two-way communication between the Neuberger Automatic Station and the SCADA system prevents unnecessary water heating. By storing energy in the form of heat, when it is most accessible, the extremely high energy efficiency of the system is achieved, which ultimately results in considerable financial savings. Active management greatly contributes to the energy efficiency of the building in the segments of electricity supply and the management of heating and cooling systems. The control is realized using smart applications developed in accordance with the Duplico M2e concept, scalable engineering solutions, and Neuberger's automation equipment for building industry. This is a practical example that solar power plant construction can be paid off in integration with low-energy heating and cooling systems, and that there is no preferential purchase of electricity. An example of relevant size tracking using the SCADA system is shown in Image 3. The increased activity of heat pumps was noticeable at the time when excess solar energy was available.
Electricity produced from solar power plants is used for their own needs, while the surplus of electricity is sold in el. network. We will also present the calculation according to which we have decided to install this system and which demonstrate the viability of investing in solar systems combined with other energy sources for the purpose of ecological production and financial viability.
Planned electricity consumption is 50 kWh per day, ie 65 kWh per day during the heating season. In daylight hours, daily production exceeds 130 kWh with an average daily output of 100 kWh. In the winter months average production is about 40 kWh per day. The second annual review of planned production and electricity consumption is shown in Table 1. In addition to the data on the amount of electricity, the calculation of the purchase and purchase of electricity at the current market prices is also given. It is important to note that this calculation was carried out without the preferential purchase price of electricity.
Unit prices [kn / kWh]: Consumption (day): 1.09; (night): 0.61; Production: 0.282 (Source: HEP-ODS d.o.o.) Detailed annual review of planned production and electricity consumption is presented in Table 1. In addition to the data on the amount of electricity, the calculation of the purchase and purchase of electricity at the current market prices is also given. It is important to note that this calculation was carried out without the preferential purchase price of electricity. In the analysis of the financial utilization of heating it is necessary to add additional costs that would exist in the case of the use of another energy source. For a building of 1013 m2 and the specific annual heat energy required for QH heating, nd = 32.67 kWh / m2, it is necessary to have 33.094 kWh for heating. In the summer months, the heat sink system with the passive cooling function is responsible for cooling the facility. According to estimates, by using a classic refrigeration cooling system in the summer months, it would be necessary to invest an additional 12 kW during the duration of the building's activity. By calculating for 3 months per year, requiring cooling, with 25 working days per month and a daily working time of 10 hours, the following amount of electricity is obtained: In calculating the cost-effectiveness of the low temperature heating / cooling system and the solar power plant, in addition to the amount of energy sold, it is extremely important to calculate the savings achieved by using energy from its own production. Thus at an annual level of 9,380 kWh extra power, additional 13,550 kWh is also used in its own consumption. The solar power plant together with the heat pump-based heating system has a total return on investment consisting of electricity produced for its own needs and sold energy, and savings in heating and cooling. The level of annual savings is calculated on the basis of the following data: Solar energy form the power plant sold + used energy from solar plant + solar energy hoist savings + the heating of the heat pumps + hoist heat recovery of the pump with passive cooling function. The energy prices are downloaded from the operator's pages. The budget presented shows that with the complete integration of the heating and cooling control system and the control of energy production and without the necessity of a preferential price of energy sales, the investment becomes financially viable. In addition to financial viability and energy saving, it is important to point out the contribution of the solar power plant to environmental protection in terms of reducing CO2 emissions. According to available data from the Ministry of Economy of the Republic of Croatia, published in 2013 annual energy review, the average specific factor of CO2 emissions per total produced electricity in Croatia in the period 2008-2013 was 0.295 kg / kWh. According to the Intergovernmental Climate Change Association (IPCC Working Group III), the average contribution of solar panels to CO2 emissions is 0.041 kg / kWh. Therefore, from the produced 22,930 kWh of electricity produced from the Duplico Solar Power Plant, annual CO2 savings are: Precisely this integrated management system is a presentation of our M2e concept, which results in automated energy management in the building, reducing energy consumption, enhancing the facility's energy efficiency, environmental protection, and ultimately the most important, financial savings for the user. Such solutions, except for business premises, are particularly interesting for use in public institutions such as schools, kindergartens, hospitals, hotels and homes, particularly with the use of EU and Government ministries to install solar power plants and increase energy efficiency of buildings. This text was published in EGE 4/2015 and 1/2016.