Mechanical Contracting Activities
Established within Üçay Group in 2005, Üçay Electromechanical has adopted customer satisfaction as its focal point by providing services across all areas of electrical and mechanical installations—from project design to commissioning—for every type of building, where such systems are now a necessity rather than a luxury. In hospitals, hotels, shopping malls, industrial plants, residential projects, and all other structures, we deliver services in electromechanical disciplines in compliance with relevant laws, regulations, and international standards, adopting as our core policy the delivery of economical, efficient, and environmentally responsible systems to our clients. In parallel with advancing technologies, we continuously renew ourselves and, with our young and dynamic team, maintain our position among the industry’s leading companies.
The scope of mechanical contracting is divided into multiple groups such as Heating Systems–Cooling Systems, Plumbing (Sanitary) Systems, Ventilation Systems, Fire Prevention & Suppression Systems, Automation Systems, and similar solutions. These systems can be installed as a whole or modularly in mass-housing projects.
Heating Systems
Radiator Heating Systems
In hot-water heating systems, the radiator is a heat-emitting device with a large surface area located at an appropriate point in the space to be heated. In widely used hot-water (central heating) systems, water heated in the boiler room typically enters radiators—often placed in front of windows—from the top and returns from the bottom, flowing back to the boiler room via return risers. The return water temperature is on average 20°C lower than the supply temperature. Depending on the comfort setpoint of the space and the heat loss, the number of radiator sections varies. Radiators come in many sizes such as 30, 50, and 100 cm. To ensure both an attractive appearance and higher heat output, aluminum finned radiators and panel-type steel radiators are commonly used.
Unit Heater (Apéry) Heating Systems
The main advantages of hot-air unit heaters are their economy, compact size relative to high heating capacity, and user friendliness. Utilizing hot water drawn from the building’s heating system or steam produced by your plant’s hot-water/steam boiler, they provide a practical and economical heating method. The heating capacity depends on the temperature difference between the heating coil and the airstream as well as air velocity—higher velocity and temperature difference yield higher capacity. With 90/70 °C hot water, axial-fan unit heaters can reach up to 35,000 kcal/h, while radial-fan models can reach up to 48,000 kcal/h.
Underfloor Heating Systems
Underfloor heating is a method where hot water circulates through pipes placed at set intervals within the screed above the slab. In certain applications, electric heating cables or mats are used in place of pipes. Unlike other heating systems, more than 60% of heat transfer occurs via radiation, providing comfortable heating even at lower room temperatures. Underfloor heating does not stir up dust nor does it support the survival of mites; it is a healthy solution. Properly calculated and correctly implemented systems create uniform, human-centric comfort conditions. Compared to radiator systems, service life is longer: thanks to PEX pipes, underfloor systems have a minimum life of 50 years depending on operating temperature and pressure, whereas metal radiators are more susceptible to corrosion.
Fan-Coil Systems
Fan-coil systems condition buildings by circulating hot/cold water in a closed loop through terminal units, where a fan draws room air across the coil and returns the conditioned air to the space. Commonly used in hospitals, hotels, shopping malls, and business centers, these systems come in two-pipe and four-pipe configurations, directly impacting user comfort and energy efficiency.
Convector Heating Systems
Convector heaters warm indoor spaces by heating air via convection. Cooler air enters channels at the bottom of the casing, passes through heated fins (resistive or hydronic), and rises back into the space through front discharge apertures, rapidly warming the environment. Convectors are suitable for seasonal homes, apartments, single rooms such as children’s or bedrooms, offices, hotels, boarding houses, cafes, yachts, boats, and many other settings.
Radiant Heating Systems
Unlike conventional convective heaters that warm air molecules, radiant systems directly heat objects and people, making them ideal for high-ceiling and semi-open/open areas where convective heating is inefficient and costly to operate. Often referred to as infrared heaters, radiant systems—initially used in industrial facilities—have, over the last two decades, become common in cafes, restaurants, sports halls, places of worship, retail stores, and showrooms. In gas-fired radiant tube systems, combustion gases transfer heat to special quartz-coated tubes; heat then radiates from the tube and is reflected to the floor via reflectors—much like the sun’s principle of radiant heat.
Heating via Air-Handling Units (AHU)
In AHU-based heating, an exhaust fan draws room air into the unit while a supply fan delivers conditioned air back to the space. Heat-recovery AHUs provide substantial energy savings. Without mixing exhaust and fresh air streams, energy is exchanged within the heat-recovery section to pre-condition the air. Two types of heat recovery are used: air-to-air and air-to-water. In air-to-air systems, energy is transferred via heat exchangers (often aluminum plate heat exchangers). In air-to-water systems, two coils are used—one on the fresh-air side and one on the exhaust side—connected in a closed loop via a circulation pump.
Cooling Systems
Variable Refrigerant Flow (VRF/VRV/VRF-type) Systems
VRF denotes Variable Refrigerant Flow systems.
DSD denotes “variable refrigerant flow” in Turkish nomenclature. VRF/VRV/DSD indicate the same technology under different brand names. A single modular outdoor unit can serve many indoor units (up to 64, depending on model). Indoor unit types—wall-mounted, cassette, ducted, or ceiling—can be freely combined. Ideal for hotels, hospitals, offices, restaurants, retail, theaters, and cinemas where loads vary and independent zone control is required. Each indoor unit uses a TXV (thermostatic expansion valve) or AEV (automatic expansion valve) for independent operation.
Split Air-Conditioning Systems
For localized needs, split AC units offer economical, rapid solutions for individual, independent spaces. Available in many models and capacities, including inverter types. Split types include wall, floor, console, ducted, concealed ceiling, and more—tailored to the conditioned space.
Fan-Coil Systems
(See description under Heating Systems.) Fan-coil units can provide cooling in summer and heating in winter, circulate air, filter it, and—optionally—mix with fresh air to improve IAQ. Wide variety: cassette/non-cassette, floor-mounted, concealed ceiling, high-static, high-wall, or four-way cassette units.
Air-Handling Units (AHUs)
For cooling, AHUs draw room air via an exhaust fan and deliver pre-conditioned supply air via a supply fan. Heat-recovery AHUs save significant energy by transferring energy between exhaust and fresh air without mixing airstreams. AHUs provide comfort by maintaining temperature and humidity setpoints and can perform heating, cooling, dehumidification, and humidification.
Radiant Floor & Wall Cooling
Reversing an underfloor heating system can be an effective way to cool buildings in summer, depending on building heat gain and system efficiency. When designing from an existing underfloor system, cooling surface area and permissible surface temperatures must be calculated. To ensure comfort, it is essential to minimize heat gains—chiefly via insulation. The better the envelope insulation, the more effective radiant cooling will be; in a well-insulated building, underfloor cooling can meet comfort requirements.
Plumbing (Sanitary) Systems
Domestic (Potable) Water Systems
The network of pipes that conveys water to points of use in a building is called the domestic water installation and is divided into two parts:
Service line (External potable water): The pipe section between the municipal main and the building’s water meter.
Internal potable water: Risers distributing water to floors and branches conveying water from risers to fixtures.
Sewage (Soil/Waste) Systems
The pipe system that removes wastewater from fixtures and conveys it to the municipal sewer—or, where unavailable, to septic/sump systems—is called the building soil/waste installation. A well-designed system removes wastewater continuously, swiftly, hygienically, and without discomfort to occupants.
Rainwater Systems
Although often overlooked, rainwater drainage must be carefully considered depending on building type. In tall buildings with small roof areas, elevation differences create challenges, while in large single-story buildings (factories, warehouses, open spaces) rain drainage becomes as critical as sanitary systems. In line with environmental approaches, collecting, treating, and reusing rainwater has become an important design feature.
Siphonic Roof Drainage Systems
Siphonic systems remove rainwater using the principle of energy balance (Bernoulli’s principle). No slope is required along gutters or roof drains, and no pumps are needed; correct design ensures fully filled pipes and self-priming flow. Design is carried out with specialized software, considering architectural sections, roof plans, mechanical drawings, and infrastructure layouts.
Fire Prevention & Suppression Systems
Sprinkler Systems
The goal of sprinkler systems is early response—controlling and extinguishing a fire by discharging a prescribed amount of water over the design area within a defined time. The key element is the sprinkler head (deflector, heat-sensitive element—fusible metal or glass bulb—and body). Common in hotels. Various types exist; selection depends on fuel type, racking, freeze risk, hazard category, required density, routing, seismic considerations, etc. Nozzle type and temperature ratings are chosen accordingly, and valve groups are arranged per system model.
Fire Hose Reel Systems
A fire hose reel system supplies pressurized water from the pump station to the nozzle at the end of the hose located within the cabinet. Its purpose is to ensure reliable and adequate water supply within the building during firefighting. Cabinets must allow easy access and operation. Placement typically ensures 30-meter coverage per reel, located near corridors and stairwells in visible positions.
Foam Suppression Systems
Foam systems—synthetic, protein-based, film-forming, and alcohol-resistant types—are used primarily for fuel and flammable liquid fires, especially where spread risk is high. Water is mixed with foam concentrate via a proportioner, then aerated under pressure within a foam generator/nozzle/monitor, expanded to a ratio dependent on foam and discharge device, and discharged to the hazard area. Typical applications: pharmaceuticals, food, rubber, printing, fuel production/storage, chemical plants/depots, aircraft/heli hangars, fuel filling stations, marine cargo/chemical tanks, shipyards, piers/marinas, refineries, defense facilities, etc.
Gaseous Suppression Systems
Combustion requires a sufficient oxygen concentration and elevated temperature. Ambient air contains ~20.9% oxygen; when reduced below certain thresholds, combustion slows and eventually ceases. Clean-agent gaseous systems are widely used to protect sensitive equipment and ensure business continuity—common in data centers, control rooms, industrial control spaces, telecom hubs, power generation facilities, archives, etc.
Hydrant Systems
Installed along streets or outside large facilities/public buildings based on area fire risk, hydrants supply pressurized water for firefighting and filling fire engines. They are fed by the municipal main or site fire pumps and must be located for easy access and connection by fire services.
Ventilation Systems
Car Park Ventilation Systems
With growing urban density and increased vehicle usage—plus complex buildings such as malls, airports, and terminals—demand for car parks has surged, particularly in basements. Two primary objectives drive car park ventilation: in daily operation, the extraction of harmful exhaust gases; and in fire emergencies, smoke compartmentation to assist evacuation and firefighting operations.
AHU-Based Ventilation Systems
AHUs condition outdoor air—heating, cooling, humidifying, dehumidifying, filtering, and recovering heat as required—before supplying it to the space. Depending on type, AHUs also filter particulates and microorganisms. Packaged AHUs are favored for their compactness and BMS integration.
General Supply & Exhaust Systems
General exhaust and make-up air systems transfer energy between exhaust and fresh air in a heat-recovery cell without mixing airstreams. Mixed-air AHUs vary the proportion of return and fresh air according to conditions to optimize energy usage.
Jet-Fan Exhaust Systems
Used in car parks and tunnels to control, direct, and extract air movement. Compared to ducted systems, they reduce installation cost, increase usable parking area, lower operating costs and noise, and are ideal for smoke extraction and ventilation. Composed of fans and acoustic attenuators.
Smoke Extraction & Pressurization
Pressurization prevents smoke ingress into stairwells and elevator shafts, enabling smoke-free evacuation and safe firefighter access. Stair cores are separated by fire-rated, smoke-tight doors; positive pressure is applied to the core to block smoke entry from adjacent spaces.
Treatment (Water) Systems
Chlorination (Dosing) Systems
(Note: The original Turkish paragraph repeated jet-fan text; translated intent provided here.) Chlorination systems are among the most common and economical disinfection methods, offering lasting effectiveness. Chlorine is chemically stable and effective against a wide range of organisms; it is injected into the system via dosing pumps.
Ultraviolet Sterilization Systems
UV disinfection is a rapid and effective method without chemical side effects: by exposing bacteria, viruses, fungi, and other microorganisms to UV radiation, it inactivates them without altering the water’s taste or composition. Efficacy depends on intensity and contact time. Typical applications include drinking water units, hospitals, restaurants, hotels, residential complexes, bottling plants, cooling towers, laboratories, food industry, and fish farms.
Water Softening Systems
Dissolved calcium and magnesium ions cause water hardness, which is removed via ion-exchange softening systems. When the resin is saturated, it is regenerated with sodium chloride brine. High-quality resins and advanced regeneration reduce salt and water consumption while delivering high de-scaling performance—protecting piping, washing/heating systems, and improving energy efficiency.
Filtration Systems
Activated carbon filters—comprising quartz and carbon granules—adsorb fumes and VOCs within local exhaust/filtration setups. Filter life depends on process type and scale.
Protection in Heating & Cooling Installations
(Note: Clarified from the chlorination description.) Chlorination dosing is widely used for disinfection thanks to its lasting effect and cost efficiency. Chlorine, injected via dosing pumps, ensures adequate disinfection across the system.
Automation Systems
Jet-Fan Control System
Based on signals from CO sensors and/or fire/smoke detection systems, the control panel operates all mechanical devices (axial fans, jet fans, smoke/fire dampers, doors, etc.) according to pre-programmed ventilation scenarios stored in the PLC (Programmable Logic Controller).
Photovoltaic Systems
Photovoltaic (PV) cells convert sunlight directly into electricity using semiconductors such as silicon, gallium arsenide, cadmium telluride, or copper indium diselenide. Typically shaped as squares, rectangles, or circles, with areas around 100/156/243 cm² and thicknesses of 0.2–0.4 mm. Thin-film cells can be applied to various surfaces in custom sizes. Depending on cell type, efficiencies range from ~5% to 20%. With no moving parts, maintenance is minimal. PV systems are environmentally friendly, silent, and enable localized generation/consumption wherever sunlight is available.
Automatic Control Systems
Control is indispensable for mechanical installations—enabling remote monitoring/operation, reducing staffing needs, and ensuring immediate intervention for energy savings and comfort. Effective control requires integrated pneumatic, electronic, and electromechanical field devices to maintain temperature, humidity, and IAQ setpoints. Field devices coordinate to modulate capacity and deliver optimum performance.
Building Automation Systems
Building automation aims to monitor and control all systems from a single interface. For medium to very large buildings, automation is typically structured into mechanical control, lighting control, and electrical power monitoring. Essential for energy efficiency, our solutions serve as a model in both lighting and HVAC. BMS also plays a vital role in safety: in fire, gas leak, flood, and similar emergencies, it rapidly and reliably alerts occupants and protects the building—saving time for stakeholders. Fewer staff can oversee all systems, lowering OPEX while maximizing efficiency with the latest technology.
Solar Energy Systems
Solar energy is inexhaustible as it harnesses the sun. Being renewable and clean, it produces no harmful smoke, gases, carbon monoxide, sulfur, or radiation. It is eco-friendly and cost-effective, with low CAPEX relative to output and high efficiency. Among renewables, solar power plants are the easiest to install, operate, and maintain. Systems can be deployed wherever energy is needed; unused roof areas can be turned into generation assets. Thanks to modularity, installation is straightforward. By reducing dependency on imported energy, solar contributes to the economy and increases income from domestic resources—maintenance costs are notably low.
Natural Gas Systems
Residential Natural Gas Systems
Natural gas is a fossil fuel found deep within the earth’s crust, consisting primarily of methane, with ethane, butane, and propane as secondary components. Residential (domestic) natural gas installations serve housing units.
Industrial Natural Gas Systems
Industrial natural gas installations are used predominantly in industry. While natural gas composition is similar, the systems differ from residential installations in scale and design—they are significantly larger and tailored to industrial processes and buildings.
Industrial Systems
Steam Piping Systems
The purpose of steam distribution is to deliver steam at the required pressure to points of use; pressure drop along distribution lines is therefore critical. Water heated to its boiling point begins to vaporize; the resulting steam must be supplied to equipment at the desired pressure, quality, and flow—achieved through properly designed and installed distribution systems.
High-Temperature Hot Water Systems
High-temperature hot-water (HTHW) boilers produce water above 120°C under pressure, typically for central systems. Maintaining target temperatures requires stable system pressure. Three-pass, flame- and smoke-tube designs offer high efficiency. Tubes are welded to tube sheets for easy maintenance. Semi-cylindrical and solid-fuel variants exist; many models can be adapted for natural gas firing when needed.
Thermal Oil Systems
Many processes require high-temperature heat transfer. While hot water, saturated steam, or superheated steam can deliver this, thermal oil provides high temperatures at near-atmospheric pressures—significantly improving safety. For 250–300°C with steam/hot water, pressures of 42–90 bar may be needed; with thermal oil up to ~300°C, system pressure is typically below 3 bar, limited mainly by piping resistance.
Compressed Air Systems
Compressed air stores energy and transfers it to remote points, converting pressure potential into mechanical energy. Widely used in manufacturing and service sectors—as a ubiquitous industrial energy carrier—in production, maintenance, shipbuilding, construction, and mining.
Dehumidification Systems
Excess humidity causes discomfort, health issues, dampness, odors, and damage to electronics. In indoor pools, evaporation and pool chemicals degrade comfort and harm buildings; surface evaporation must be extracted and indoor RH maintained below ~60%. Dehumidification systems regulate humidity in indoor pools, gyms, baths, and other high-humidity areas.
Medical Systems
Hospital HVAC not only provides comfort but also minimizes microorganisms, particulates, anesthetic gases, and odors. Operating theaters require highly sterile conditions; to reduce infection risks and maintain specified concentrations of microorganisms, dedicated climate control systems are essential.