More information
Description
The project "Installation of a system of heat pumps with seawater for the needs of the City Pool in Dubrovnik" predicts the reconstruction of the engine room in the said building. The goal is to replace the old fossil fuel oil technology with a modern renewable energy system that provides a continuous source of heating with seawater that acts as a stable and reliable heat source and abyss. The use of the sea, as an inexhaustible heat source, is ensured in an indirect way, by hydraulic separation of the circulation through the heat pump in relation to the circulation of seawater. The newly planned heat pump as the main consumer should have an energy efficiency of expected SCOP = 7.05. Viewed on an annual basis, the reconstruction of the mechanical system using the sea using heat pump technology to heat water in large and small pools and heat the facility itself could save almost 100% of total annual fuel oil consumption. The installation of sea-water heat pumps for heating the Gruž basin would significantly reduce CO2 emissions to 656 tons per year, which is a reduction of 89%, and in addition to positive effects at the global level would contribute to improving air quality locally.
Summary of project results
In the wider area of the Dubrovnik-Neretva County, the Gruž city pool is the only covered pool used by sports clubs, as well as recreational users. For many years, only fuel oil was used for heating, which creates large economic maintenance costs, but also a significant negative impact on the environment. The city pool is an Olympic-sized pool with dimensions of 50 meters in length, 25 meters in width and 2.5 meters in depth. The construction of the pool began at the end of the fifties of the 20th century, and was completed in 1961. Within the facility there is also a small paddling pool, 18m long and 5m wide. The volume of the small and large pool is slightly more than 3,200 m3, and maintaining a constant temperature of 27⁰C is a problem in the form of high energy consumption required for heating. Part of the equipment used to heat the pool in the engine room was from the time the pool was built.
The goal of the project was to replace the old fossil technology, which uses heating oil as an energy source, with a modern system that would use renewable energy sources, more precisely with a modern seawater/water heat pump system of equal capacity. The heat pump provides a continuous source of heating with seawater which acts as a stable and reliable heat source .
The main project for the replacing old heating system with the renewable one included coordination between mechanical engineering, electrical engineering, construction-craft works and the construction of AB wells and drilling works. The heating oil boiler system was replaced by heat pumps - seawater/water. The required capacity of water-to-water heat pumps of 1.2 MW was achieved with two devices with a capacity of 600 kW each. In the heating mode, the system uses the thermal energy of the sea as a renewable source of heat. Due to the corrosiveness of seawater, the seawater does not go directly to the evaporator of the heat pump, but previously transfers heat to a corrosion-resistant intermediate exchanger. The heat on the evaporator is transferred to the working substance and raised to a higher energy level, and then transferred to the heated space. Seawater intake is one of the most important parts of a heat pump system with seawater as a heat source, since the continuous and stable operation of the heat pump depends on a continuous, stable and sufficient supply of seawater. The seawater intake system consists of 2 exploitation wells and 2 absorption wells up to a depth of 50 meters. From the exploitation wells, sea water is transported via PEHD pipe network with pumps into the boiler room area to the plate exchangers, where the heat is transferred to the heating water. Water meters were installed on the way out and back in order to monitor water consumption, i.e. whether all the seawater taken from the exploitation wells was returned to the absorption wells. In the boiler room, the existing tanks of 3000 liters were replaced with two (2) new energy tanks of the same volume.
Also, as part of the project, 3 workshops were held, promotional material was purchased and the project website was created.
As part of reconstruction of the engine room at the Public Pool Gruž in Dubrovnik, the old oil-fired hot water boiler system with a capacity of 1.2 MW was dismantled and replaced with a new modern sea water/water heat pump system of the same capacity. The maximum power capacity of each installed heat pump is 635kW, meaning that combined we achieve 1270 kW. So far, the total thermal energy of 1,955 kWh has been obtained through heating oil boilers, which is equivalent to the annual consumption of 230 t of heating oil. Now the same thermal energy of 1,955 kWh will be produced through the water/water heat pump system.
Seen on an annual basis, the reconstruction of the mechanical system by utilizing the sea with heat pump technology for heating the water in the large and small pool and heating the building itself will save almost 100% of the total annual fuel oil consumption. According to the calculation in relation to the current fuel oil prices and the total consumption of fuel oil in the past years, the annual savings will amount to approx. 200,000 EUR, which is a significant saving for the user.
The emission of CO2 into the atmosphere will be reduced in the amount of 656 tons per year, which is a reduction of 89%, and in addition to positive effects at the global level, it will also contribute to the improvement of air quality at the local level.
The users of the swimming pool are water polo clubs, swimming clubs, high schools for physical education and health education, people with special needs and recreationists.