The study gives an overview of the possibilities of installing a turboexpander-electric generator assembly in the gas withdrawal line.

Potential energy savings at the UGS Okoli (underground gas storage) site were considered on an annual basis in two different scenarios: by installing a turboexpander to cover the site's electrical consumption and by installing a site's maximum available power assembly with excess electrical energy to be used for hydrogen production or as an assistance to the existing boiler room.

Key words: underground gas storage, gas pressure potential energy, turboexpander, electric energy savings, electrolysis, hydrogen production

TEHNOKOM donated to the Faculty of Mechanical Engineering and Naval Architecture of the University of Zagreb a reversible absorption heat pump powered by gas made by renowned Italian manufacturer ROBUR. The donated equipment will be used for student works, as a demonstration example of the operation of a gas absorption device and for holding seminars by experts in the field of heat pumps. Along with the device itself, a operating scheme of the device in heating and cooling mode will be exhibited.

The first steps of cooperation with TEHNOKOM are realized by interested students of the Faculty of Mechanical Engineering and Naval Architecture through professional practice or by performing student affairs. For most of them, this is one of the first opportunities to put their theoretical knowledge into practice, thus adding a new dimension to the area of interest. TEHNOKOM thus offers students the opportunity to become acquainted with numerous experts, many innovative technologies and technical solutions, as well as the sales program it offers. Students interested in learning and applying their theoretical knowledge to practice are always welcome, just as those who are eager to develop their skills through work experience.

TEHNOKOM guarantees students the possibility of flexible arrivals throughout the academic year. The practice can be done in different departments, depending on the field of study and interests:

• design, engineering and consulting
• maintenance and management of energy systems
• sales, installation and service of equipment

Full-time students of the 1st or 2nd year of graduate study in Mechanical Engineering and Naval Architecture may apply.

The need for more efficient cooling and heating of M San's business building resulted in the replacement of already outdated HVAC system.

Two high-performance two-stage gas absorption chillers YAZAKI with a power output of 350 kW and 210 kW have been installed.

A project solution in which two different power units were combined was selected to ensure system redundancy and ease of adaptation to the variable thermal oscillation of the facility.

The cascading central control and monitoring system of the absorbent installation with the possibility of remote access via the Internet has been integrated, which largely ensures uniterrupted operation of the system.

Consulting, equipment procurement, and commissioning were carried out by Tehnokom's engineering team.

The 32nd International Scientific & Expert Meeting of Gas Professionals, organized by the Croatian Gas Centre Ltd. and Croatian Gas Association was held from 3rd to 5th of May, 2017, at the Congress Centre of the Grand Hotel Adriatic, Opatija, Croatia.

Three-day international gas conference and exhibition, the largest annual gas event in South-East Europe gathered about 600 renowned experts and managers from about 230 companies, organisations and institutions actively inolved in the energy and gas industry of Croatia and about 20 other countries.

The main topics were:

1. Energy strategies and the future of gas in the energy industry
2. Smart technologies in gas and energy systems
3. Development of the croatian gas infrastructure (gas pipelines, compressor stations, gas storage, chromatographs and LNG ships)
4. Various issues in the gas profession
5. Supplying gas in a fully liberalized gas market and the consolidation of gas suppliers
6. Gas distribution systems and related issues
7. Various intersting presentations on the gas industry
8. Technical regulations and rules of the profession for safe and efficient gas utilization

Experts in the area of gas industry, designers as well as our business partners visited Tehnokom stand where ROBUR gas heaters/chillers and GESTRA steam and condensate systems were presented.

In order to increase the energy efficiency of the building, renovation of HVAC installations is made on Karlovac County Chamber (900 m2). Tehnokom prepared the basic and detailed design, delivered equipment and performed works.

The aim of the project was to provide savings which are achieved by changing the technology of heating and cooling. The existing oil boiler and cooling system VRV is replaced by gas absorption reversible heat pumps ROBUR GAHP AR, heating power of 105 kW and cooling power of 52.5 kW. The existing radiator heating system and the inner cooling wall unit is replaced by two-pipe fan coil parapet.
In the conference room is built recuperative unit for air exchange capacity of 2500 m3/h with an additional heat exchanger for cooling or heating of the consitioned air.

Expected savings in primary energy (gas), compared with the old system of heating and cooling, is about 50%.

Tehnokom Ltd. participated at the 16th Gas Conference in Zagreb. More than 250 participants from the field of gas business attended the Conference and discussed about the substantial increase in gas prices in the coming period and the further liberalization of the gas market as well as the issue of security of gas supply in Croatia.

Josip Kopejtko M. Eng., from Tehnokom Ltd., held a very interesting presentation about new product on the Croatian market - K18 absorption heat pump for domestic use.

The application and various benefits were presented through examples. We are glead that paricipants were interested in K18 and could obtain more technical information with promotion material at Tehnokom's exhibition place.

The product is very interesting private homes, smaller buildings and family hotels.

30th of November Tehnokom finished Legalization of high hazard level piping systems project at two thermal plants and one electric power supply & thermal plant, all owned and operating by HEP, Croatian Electric Power Supplier Company.

Contract has finished 72 days earlier even was number of high hazard level piping systems increased for 41.17%; TPP Rijeka 34 piping systems instead contracted 20, TPP Plomin 35 piping systems instead contracted 30 and EPP – TPP Zagreb 51 piping systems instead contracted 35 systems.

120 high hazard level piping systems have been elaborated with related calculations, drawings and design to satisfy new EU Norm and OPT Agencija (OPT = Authorized body for pressurized equipment) requirements.

Tehnokom Ltd. paritcipated on 12th. Inernational Symposium „Power and Process Plants“ and the 7th International Forum on Renewable Energy Sources in Rovinj, Novmber 16 - 18, 2016.

At Tehnokom's exhibition place were presented renowned manufactures of heating, cooling and domestic hot water equipment based on the principle of exploitation of renewable energy sources and steam equipment.

Mr. Zglavnik Dipl. Ing., held a very interesting lecture entitled „Who is responsible for global warming?“ in which he presented the work of a much smaller number of scientists dealing with climate issues, but who don't have the institutional, material and media support for their work and think that the temperature rise on Earth is actually a natural cyclic process, a result of changes in the Sun that governs the Earth's climate and human activity on the global climate influences slightly or not at all.

That theory directly questiones the Kjoto Protocol by which industrialized countries set the goal for reducing the emissions into the atmosphere of gases that cause the greenhouse effect and temperature rise on Earth.

Josip Kopejtko, mag. ing. mech., held a lecture entitled „Effective and simple solutios for heating and cooling using renewable energy sources“.

Solutions for heating, cooling and DHW heating using a high-efficiency gas absorption devices that use renewable energy sources were presented on various examples.

ADIPEC is home to one of the world's biggest and most important technical conferences with over 106 technical sessions and 850+ speakers in 2016.

The reason of presence was to create the opportunity to network extends at UAE area and Middle East in general, even beyond the conference programme, where was present over 2,000+ exhibiting companies, and to present our technical knowledge and experience globally to industry colleagues and raise our company's technical profile at a prestigious industry event.

Tehnokom has presented activities in oil & gas industry at the both side - onshore and offshore, thermal and process plants, refineries process simulation and upgrade options, energy sawing and solar energy.

Tehnokom has established rich and fruitful communication and contacts with 48 companies, mainly based in UAE, Iran, Oman and Bahrein region but also present worldwide as well.

Tehnokom's team is already working on offered business opportunities and knowledge exchange, created during the stand visit.

Organized by the Equipment Under Pressure Council, part of the Croatian Chamber of Mechanical Engineers at October 25, 2016, in Zagreb was held Training of personnel involved in the preparatory work for the periodic inspections and tests of pressure equipment Module 1: Basic training - General Part.

The training was attended by over 130 participants: owner / user of pressure equipment, designers - authorized engineers; technologists and operators involved in the maintenance of pressurized equipment and in the preparatory work for the periodic tests; manufacturers of the equipment under pressure; inspectors involved in the review and pressure equipment testing.

Tehnokom was presented with a lecture on the topic: Preparation of project documentation for existing pipelines in use in accordance with the Regulations on the inspection and testing of pressure equipment (Official Gazette 142/14), with review of the current situation and practice experiences, held by Nenad Zivkovic, msc.mech.eng.

31st International Scientific & Expert meeting of Gas Professionals, organized by the Croatian Gas Centre Ltd. and Croatian Gas Association, was held from 4th to 6th of May, 2016, at the Congress Centre of the Grand Hotel Adriatic, Opatija, Croatia.

A three-day, international gas conference and exhibition, one of the largest annual gas event in South-East Europe gathered about 500 renowed experts and managers from about 200 companies, organisations and institutions in Croatian energy and gas industry and from about 20 countries.

Company Tehnokom at its exhibition area presented the project of a modular portable gas absorption cooling / heating plant for the processing of raw gas built on INA -KS Šandrovac, the first facility of this kind in Croatia, where the equipment of the manufacturer ROBUR was installed.

At the conference Ph. D. Svetlana Petrović from INA- Industrija nafte d.d. held a lecture titled „Cooling Unit for Gas on CS Šandrovac - Process of Cooling of Natural Gas with Absorption Chillers (With Low Electricity Consumption) in Target to Ensure Required Quality of Gas Supply".

Hotel Vila Rova is a family hotel located on the island of Krk, Malinska-Dubašnica, with a capacity after the reconstruction of 46 basic and 12 additional beds, with planned season of nine-months.

From the early beginnings of the year 2013, company Tehnokom ltd. was involved in the project of reconstruction of the hotel Vila Rova. For that matter Tehnokom made energy analysis of the hotel and the use of renewable energy sources before the main project to prove the feasibility of the reconstruction and improvement of energy efficiency.

Also the main engineering project was made, the feasibility study and detailed engineering project but also the preparation of documentation for the project application for the co-financing from EU funds.

The largest annual gas event in South-East Europe, organized by the Croatian Gas Centre Ltd. and Croatian Gas Association, celebrated its thirtieth anniversary and gathered more than 500 participants from 20 European countries.

Those were mostly gas and energy experts, managers from leading European energy companies, scientists from renowned European universities, gas transmission representatives, suppliers, producers and distributors of gas as well as representatives of large gas consumers and producers and traders of gas equipment and solutions from Croatia and abroad.

Totally 208 various gas and energy companies and organizations were present, of whom 85 from abroad.

The company Tehnokom Ltd., the traditional participant of the Conference, this year was presented by commercialy-technical presentation „Solar cooling using absorption chillers“ and its stand on which were exhibited gas absorbers and gas heaters.

Miljenko Baborsky, B.Sc.Mech.Eng., in the presentation introduced the technology of solar cooling, the potential for energy savings with the emphasis on „Green energy“ and pointed out its advantages.Also, the projects of solar cooling in Croatia and the region carried out by Tehnokom were presented.

We hereby thank all our business partners and associates who visited us!

From 12th to 14th of November in Rovinj was held 11th International symposium Power and process plants and the 6th International forum on renewable energy sources.

Within symposium a professional trip was organised- a tour of the thermal power plant Plomin.

Company Tehnokom was presented with two lectures and its completed projects in the field of renewable energy sources. It hosted numerous experts at its boot.

Mijo Zglavnik,B.Sc.Mech.PE, held a lecture on the subject „Geological storage of CO2 as a measure for reduction greenhouse gases emission“primarily in power plants but also in large industrial facilities.Developed countries should by the year 2020 reduce greenhouse gas emissions by 30% and by the year 2050 to 60-80%.

Miljenko Baborsky,B.Sc.Mech.PE, presented in his lecture „ Absorption cooling equipment in solar cooling technology “ installations implemented in Croatia and the region as a first of its kind which are financed by the EU under the title „ ADRIACOLD“.

Symposium participants had the opportunity to experience e-mobility live and try out a few electric vehicles, scooters and electric bikes.

Company Tehnokom Ltd. as a contractor of solar cooling project has put into operation the boiler room in the building of Thalassotherapy Crikvenica which is the second project ADRIACOLD entitled „Application of cooling technology through solar energy in the Adriatic regions“ financed under IPA Adriatic CBC.

Prefect of Primorje-Gorski Kotar County emphasized the importance of investment in order of reducing costs.
The delegation which included representatives of REA,designers,contractors,foreign partners and the head of the department for regional development, infrastructure and project managment of Primorje-Gorski Kotar County Mr. Ljudevit Krpan visited the boiler room accompanied by the director of Thalassotherapy Mr. Damir Lončarić.
This project is an excellent example of utilization of renewable energy sources where Thalassotherapy today meets over 40% of energy needs.

Technical data of the project:

Built-in single-stage absorption device with a refrigerant solution of water/LiBr with nominal cooling power of 17.6 kW manufactured by Yazaki-Maya-model WFCSC5. The system works with optimum heating water temperature of 88C. The system produces cold water with temperature of 12.6C. The installed electric power of the cooling device is 0.05kW.

As a heat source it is using six solar fields with 3 vacuum collectors manufactured by Viessmann, type Vitosol 200-T, with total absorption area of 60m2. 40,7 kW cooling tower is installed in order to remove the waste heat from the refrigerant unit.

The solar thermal energy in form of hot water is beeing send throught the plate heat exchanger and stored into the 3m³ heat storage tank from where it is transported to the absorption unit using circulating pumps. Finally, cold water from the absorption unit is sent to the building throughout existing fancoil pipelines where it is delivered to the consumer in the form of comfortable cooled air. 1m³ chilled water storage tank is installed into the chilled water syst

Due to safety reasons, parallel cooling system is installed using the existing heat pump with 14,64 kW of cooling output which is turned on regarding system power demand. During the winter season, heating demand is provided using existing heat pump with 16,11 kW of heat output. In a period when the solar fields provides sufficient energy for heating, it's generating energy from the solar field.

From 13 - 17th October 2014. 1st Energy Week took place in Dubrovnik. Organized by the Development agency of Dubrovnik (DURA), the city itself and the Environmental protection fund.

Tehnokom Ltd. participated at the „Dubrovnik Eco Energy 2014“ fair presenting the project of solar cooling implemented on the roof of the building Water supply of the city of Dubrovnik as well as the other four solar cooling projects in Slovenia (kindergarten in Piran, Kobarid, Hospital for pulmonary diseases Sežana) and the building Thalassotherapy in Crikvenica.

The city of Dubrovnik has become part of a global plan to increase energy efficiency.The purpose of Energy week is development of awareness of the citizens of the City of Dubrovnik and its surroundings on various application possibilities of energy efficiency and renewable energy.

Tehnokom Ltd. at its exhibition space in the Palace Sponza presented various possibilities of exploiting renewable energy by using absorption heat pumps for residential,commercial and other objects as well as solar cooling projects.

In the absorption technology of solar cooling the application of solar cooling has become the most discussed application. The reason for this is the use of solar radiation as the energy source of the drive that is free and renewable energy source. Thus this technology acquires the status of " Green energy". Also good circumstance of this technology is the simultaneous cooling demand and the available solar radiation (cooling during the day in summer).

Company Tehnokom as an authorized distributor of Yazaki - Maya , during the spring of the year 2014 supplied and installed complete equipment and commissioned the entire solar plant cooling business in the object " Vodovod Dubrovnik " in Dubrovnik.

The implementation of the EU project entitled " ADRIACOLD " financed from the EU IPA ADRIATIC - CBC , implemented by DURA so the city of Dubrovnik became the first city of the Adriatic region which has commissioned a solar plant for cooling the buildings.

The single-stage absorption refrigeration unit with working fluid water / LiBr nominal cooling capacity of 17.6 kW was embedded, manufactured by Yazaki - Maya - model WFC SC5 . The system works optimally with heating water temperature of 88 ° C. The system produces cold water temperature 6/12 ° C. Installed capacity of the cooling device is 0.05 kW .
As a source of heating it is used energy solar field of six batteries at three vacuum collector product Vissmann Vitosol 200 - T of the total absorption area of ​​60 m2 . For removal of waste heat from the refrigeration unit is installed wet cooling tower performance 40,7 kW .
The received energy of the sun across the plate heat stored in the heat storage tank volume of 3 m3 , and by circulation pumps leads to the absorption unit. Cold water from absorbing device is supplied in an existing building installation of fan oil. On the cold side is integrated inertial tank volume of 1 m3. Due to the necessary security as a parallel security system for cooling, it is used the existing heat pump of cooling capacity 14.64 kW, which optionally includes the work.

To heat the building in winter, heating is also provided by the existing heat pumps heat output 16.11 kW. At a time when the solar field provides enough energy for heating it uses energy from the solar field.

Full property operation of the heating and cooling controls the automatic regulation. The project incorporated the necessary measurements of various technical parameters of the cooling system, solar collector systems, and environmental parameter, as required under the EU project " Adriacold ".

This concept plant is used in summer and winter, by that it is achieved that apsorption cooling is in continuous operation for over 5 months, which contributes to the high efficiency of the plant.

Traditionally, the company Tehnokom participated in the 29th International Gas Professionals Meeting, 7-9 May, 2014, Congress Centre of the Grand Hotel Adriatic in Opatija, Croatia.

At the meetings, through scientific and professional lectures, panel discussions, roundables and other way of exhibiting, it was discussed about the latest developments and trends in the development of the gas in Croatia, Europe and the rest of the world.

The meeting was followed by the largest exhibition of gas equipment in Southeastern Europe which gathered 30 local and foreign exhibitors, mainly manifacturers and dealers of gas equipment as well as many other reputable companies which are present in the gas market.

Company Tehnokom presented the range of heating and cooling systems of the italian manufacturer ROBUR.Tehnokom is the general agent for the company ROBUR in Croatia.

Again this year a tree-day trip for designers and subcontractors was organized by Tehnokom Ltd. to the italian company ROBUR.

Professional program was very interesting and varied. Designers had the opportunity to visit the facilities such as Chamber of Commerce in Padua, nursery near Bergamo, Bergamo Hotel Bes and the old fort - Museum of Bergamo, where absorption heat pumps, absorption refrigerators and condensing boilers ROBUR in combination with solar collectors and photovoltaic cells were installed.

The main goal was to see the variety of built projects where ROBUR devices were installed in order to show significant opportunities for energy savings. In the ROBUR factory professional presentation of ROBUR program was held, followed by a production line tour. With our great hosts, professional journey ended with a tour of the old town of Bergamo and its surroundings in a cheerful atmosphere.

We would like to thank everybody for joining us this year!

Tehnokom participated on 3rd International Congress Mechanical Engineers' Days in Šibenik, May 22nd - 26th 2013 with the topic "Who is responsible for climate change on Earth".

The Congress was organised by Croatian Chamber of Mechanical Engineers where paricipants had an opportunity to exchange experience and discuss the topics such as:
Control of relevant project requirements, Energy efficiency in building construction and industry, Energy facilities and sustainable development, Technological and process plants - state - of - the - art, ecc.

Tehnokom Ltd. took part on 28th International Scientific & Expert Meeting of Gas Professionals in Opatija, Croatia, May 8-10, 2013.

Main topics were: Natural gas and renewable energy sources, Various important news from the gas industry, Planned development projects and experience in the construction of the gas transmission system and gas storage facility, Current state of an open gas market, Design and construction in the gas industry, Development activities in gas (energy) industry, Legislation, directives and new solutions in smart technologies, Technical regulations andrules of the profession for safe and efficient use of gas.

Prominent experts in the area of gas industry as well as our business partners were hosted on Tehnokom stand where Robur gas heaters/chillers that use RES were presented.

On November 23, 2012 our expert engineers and maintenance team together with Mr. Ishida - main engineer of Yazaki Ltd., commissioned Yazaki apsorption chiller-heater in a hospital for lung diseases "Sežana", Slovenia.

The hospital is a good example of efficient use of renewable energy sources, by means of Yazaki absorption chiller-heater that uses heat form solar cells, enabling significant reduction of energy costs as well protecting the environment.

Tehnokom Ltd. presented a range of gas absorption chillers and gas heaters ROBUR on Međimurje enterprenurs' fair, where potential customers had a possibility to inform themselves in detail about the working principle and installation of devices as well as information on major potentials for energy savings by using ROBUR devices making them the leader on the market, and distinguishing ROBUR from his competitors.

Traditonally Croatian water and waste water association under the auspicies of Croatian ministry of agriculture, and Hrvatske vode organize their annual Professional business conference with international participation "Current issues in water supply and sewage".

Tehnokom and it's partner TALIS group with it's brands Erhard, Strate, Bayard and Belgicast are general sponsor of the Conference. Through our sponsorship and participation, we want to support the Conference and gather all prominent institutions, experts, designers and business peple in the field of Water and Wastewater.

We invite you to visit our Tehnokom-Talis stand where professional presentation will be held with emphasis on sewage pumping stations with solid separtaion chamber, as well as professional presentations of the production program and latest technology solutions.

From 16th to 18th September 2012, company Tehnokom was visited by Mr Kris Holla (CSO, TALIS group), accompanied by Mrs. Natalie Ehrentaller, Area Sales Manager for Eastern Europe & Austria Talis Group.The purpose of the visit was signing of the agreement for a long-term business cooperation between Tehnokom and TALIS Group.

Based on successful business cooperation with renowned company Erhard, Germany (one of the members of Talis Group) the decision has been made to extend cooperation with other group members of TALIS who has as well interest in expanding to the Croatian market.

The result is an exclusive distribution agreement for the programs Erhard, Strate, Bayard and Belgicast that was signed on 18th September, 2012 by Mr. Mladen Novakovic (CEO Tehnokom) and Mr. Kris Holla (CSO Talis Group).

This agreement is important step for both sides in offering cutting-edge technology solutions in the field of water supply, sewage and hydro power on Croatian market.

As a continuation of more than a decade of very successful collaboration with the renowned Italian manufacturer ROBUR, the common decision has been made that Tehnokom becomes a distributor on Croatian market for gas fired heaters from 01 July 2012.

Gas fired heaters ROBUR already have their prominent place on Croatian market for many years.

We believe that our extensive experience, quality service as well as our reliable after-sales service, will significantly increase the presence of this renowned brand.

IFAT ENTSORGA is the most important trade fair for water, sewage, waste and raw materials management. It is remarkable for its large number of visitors from 180 countries and exhibitors from 54 nations. Except for brands (ERHARD, BAYARD, BELGICAST) that are traditionally present on croatian market, new technological solutions of sewage pumps STRATE were of special interest to our business partners from Croatia.

Thanks to this interest a visit to several plants near München was organized. Visitors had possibility to exchange impressions with expert_producers of sewage stations and municipal organizations in Germany.

There was a great atmosphere on the stand where high-profile presentations and business meetings were held and it was enriched with „Talis party evening“ where numerous business partners relaxed thanks to kind hosts, excellent cuisine and sound of „easy listening jazz“.

Tehnokom Ltd. organized a 3-day visit for designers and architects to the Italian company Robur on 17th of November 2011. They had possibility to see the plant, new product range and to visit some objects where Robur products are installed e.g. heat pumps, apsorption chillers and condensing boilers combined with solar collectors and photovoltaic cells.

Robur's experts made presentation on such topic as: basic pirinciples of work of heat pumps and how they can be combined with other devices in order to reach optimal heathing and cooling results.

The visit has been a great success and important step towards further promotion of Robur in Croatia.

Tehnokom Ltd. and Talis group are this year's main sponsors of the professional business conference with international participation "CURRENT ISSUES IN WATER SUPPLY AND SEWAGE" - October, 26 - 30, 2011 - Vodice, Croatia.

The conference is a central annual meeting of experts from the field of water management, i.e. water supply, sewage and wastewater treatment segment of the public utility services sector and it represents a leading event in the water supply and sewage industry, not only in Croatia but in the whole region of south-east Europe.

We are looking forward to seeing all our business partners at GVIK 2011!

In late August 2011, general reconstruction of the cooling system in hydro power plant GOJAK was completed.

Tehnokom Ltd. was a contracted supplier for isolating and regulating valves made by well known german company - Erhard which is represented by Tehnokom on Croatian market.

Tehnokom delivered more than 100 valves to the main contractor: Roco butterfly valves, Multamed gate valves and RKV control needle valves, most with an integrated Auma electric actuators in sizes from DN 50 up to DN 150.

From 1st January 2011 Tehnokom took over maintenance of the energy sector in Croatia's largest pharmaceutical company Pliva. We are implementing a 24 hour monitoring the energy system, perform the emergency interventions, planning and organizing regular services.

In conducting these activities, we organize supply, storage and replacement of filters and spare parts.