Why Central Heating?


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Izgaz Central Heating


WHY NATURAL GAS HEATING?

Heating with coal or liquid fuel heaters in housing causes heating from single point and low thermal efficiency and energy waste. 40-45% thermal efficiency in coal heating boilers increases up to 70-74% when the boiler is transformed into natural gas. If the boilers that lost their economic life are renewed with the boilers that are compatible with natural gas the efficiency increases up to 80-110%. Operating is easy because human factor is minimised in operating natural gas boilers therefore controlling is very easy. They enable rational and balanced heating. Having an automatic control panel on the installation is recommended to enable fuel economy in central heating system. These control panels enable heating according to the inside and outside ambient temperature. Heat transmission is fast in natural gas appliances therefore it enables efficient heating and economic usage. Bu these panels can not be installed on coal burning central systems. The equipments (three or four-way mixtuer valve, shunt, pump etc) that are installed on the system should be used in line with the recommendations and requests of the manufacturer company. In buildings which are heated with coal or fuel-oil, burning degree is adjusted by hand. But increasing or decreasing the fire of the boiler for outside heat changes cause late heating or high heating and this increases the fuel consumption.

Buildings that do not use natural gas yet are heated with coal or fuel-oil boilers. Natural gas has more advantages for economic, clean usage. When the apartments are heated with a common heating boiler by using additional appliances like hot water meter, the occupants can share the amount read from the gas amount. But if this is not used some other criterion will be used (like dividing into m2) as in coal and fuel-oil use.

When natural gas is used in radiators with thermostatic valve it enables comfort and big amount of fuel saving. It is recommended generally for the buildings that have 8-10 or more independent sections in terms of initial investment cost and operating the installment. As it is known individual heating systems cost more than central heating. The advantage of central heating is that it heats the mass. It means that it heats every part of the building. Individual system heats the place. This decreases the efficiency. There is a belief that hot water usage is not possible. Hot water can be used with hermetic heater. A good boiler room has almost the same price with combi boiler prices. Individual system may cost 3.500-4.000 TL with all its equipment whereas this cost is 1.000-1.250 TL per apartment in central system. One of the points that people are suspicious about central system is people may not pay their fee on time. Therefore people prefer to pay individually to have the control. For example a building of 20 apartments that are 100 m2 has a 250.000 kcal/h capacity need for boiler. In this boiler every day approximately 50 m3 gas is consumed. But if you install 20 combi boilers this capacity need is 20.000 kcal/h and each of them makes 400.000 kcal/h. If each of them consumes 3 m3 gas it makes 150 m3 in total.

There is not much price difference between natural gas appliances but in terms of quality there are big differences. Besides the quality of the installation is important as well. This quality can create 10-20% efficiency difference. Clients should pay attention to that. According to the building structure you can decide how much you will consume.

All the appliances must be maintained on time. Condensation in central system is quite useful and it enables 30-40% efficiency as well. When the water condensates in the boiler, water does not cool and you consume less fuel and increase the efficiency. Condensing combi boiler is more efficient compared to classical combi boiler because latent heat in condensation is recovered with a special heat exchanger that condensates the steam in condensing boiler. In these boilers stack gas exit temperature is 40-50°, in the traditional ones it is 140-160°. Since stack gas temperature is low in condensing boilers heat losses during the burning and installation are lower.

What is cascade system?

The material that is used in condensing boilers is different than the ones in other boilers. Cost of these special materials increase as the boiler size gets bigger. Cascade system resolves the huge costs of big boilers. The system is consisted of more than one appliance according to your installation need. The appliances work side by side in modulation. Cascades that work interconnected and with proportional control can be more economic than the one big boiler in terms of investment. Therefore using 2 cascades of 54Kw instead of one boiler of 100Kw will cost you less. It is possible to operate wall type condensing boiler together up to 25 in cascade system.

 How does the condensing cascade system work?

All the appliances work in proportional control in cascade system. To be able to control all the boilers at the same time they need to be connected to control unit. When there is a change in the defined room temperature, first boiler activates and works with 100% efficiency. The system checks how long it takes to reach the desired temperature. It compares this time with the targeted time that is defined previously. If the system decides that the working boiler can not reach the desired temperature in this period it activates the second boiler in a minimum level and tries the keep the target. Same procedure is repeated until the installation reaches the defined temperature in the targeted time. If the working boiler stops because of a breakdown next boiler activates automatically and it does not cause a malfunction.  The capacity of cascade system is equal to the total of all the capacity of boilers. The boiler that are connected in series heat the same heating system. It is a must to have hydraulic separator on the installation that use cascade system. You can also combine the different capacity boilers and create a cascade system you target to have. Cascade boilers can be installed on the wall that’s why they do not occupy place. Thanks to electronic control system temperature of the many places can be adjusted at the same time. Therefore your heating cost decreases and it makes a huge difference on the invoice.

You can find the advantages of the cascade system below;

  • Room temperature control sensibility is  ± 0,1 C.
  • The appliances change turn in every 24 hours. All the appliances work in equal period.
  • These systems have total modulation burner and these burners are adjusted as proportional with air and fuel. Modulation burner and fan control the capacity.
  •  The system has also line control advantage. The capacity can be controlled consistently between 2% and %100. Between 0-2% proportional capacity control is provided with pump modulation. By way of pump modulation that is performed parallel to the burner modulation amount of water that goes in the system and the losses decrease.
  • Primer pumps are very small therefore electricity consumption is low.
  • It occupies less place.
  • Radiation loss is small because of its small trunk.
  • In single zone heating systems and single zone heating + boiler systems there is no need for mixer 3 way valve and its accessories.
  • Flame temperature is very low therefore NOX emissions are under 20 mg/k Wh.
  • The system has always a backup.
  • It is advantageous in flue connection because hermetic flue connection is possible. Each appliance can be connected to the common flue. They can also be connected one by one.
  • Water volume of the appliances is low therefore it reaches to desired exit water temperature.
  • Burning occurs with fan therefore it is possible to design flue as positive pressure. With this way it is possible to calculate smaller flue diameter.
  • Air-fuel mixture is done pneumatically therefore it is not affected from flue draught. It does not require burner adjustment in season change.
  • It is not necessary to take precautions for return water and condensation. First investment cost is low.
  • Thanks to logomatic panel highly sensitive capacity control (heat generation) which is 100% compatible with the system capacity, it provides the most efficient operation.

 

Heating Boilers

Heating boilers are separated into two main groups as sectional cast iron boiler and steel according to their materials. Heating boiler choice is one of the problems when shifting to natural gas. When you look at the European counties that started to use natural gas long before Turkey you see that both types are being used for long years. Many companies that manufacture these two types of boilers have carried on their activities and found a place in the market. This means that both types of boilers have advantages and disadvantages but they have a place in natural gas market. Shifting to natural gas is not only a matter of boiler choice. It is also a choice of whole system with boiler, burner, flue, valve, automatic control, security systems, insulation, piping and pump. This system should be chosen in the best way.

 

Types of Heating Boilers According to the Material

Boilers are separated into two main groups as sectional cast iron boiler and steel according to their materials;

Sectional Cast Iron Boilers

These boilers can be carried and installed easily to the boiler room because of their sectional structure. It is also possible to increase the capacity by addition of section. It is possible to choose boiler according to the need. When these kind of boilers are imported they need to be comply with DIN 1691 and 4702 norm,  local ones should comply with TS 430, 4040 and 4041 (thermal efficiency).

 

Steel Boilers

They need to comply with TS 497, TS 4040, TS 4041 (thermal efficiency, capacity) standards. For the boiler houses that have narrow entry it is hard to put the monobloc products. For the products that the installation is done on site, terms of guarantee of the manufacturer company should be reviewed.

 

Heating Boilers According to the Burner Type

 There are two types of heating boilers according to the burner type which are blown burner and natural draught burner. These burners can be applied to both steel boiler and sectional cast iron boilers.

Blown Burner Boilers

It is possible to use alternative fuel (Fuel oil, diesel oil, LPG) without changing the boiler. With addition of section capacity increase in sectional cast iron boilers may not require burner change. In these kind of burners combustion air is taken via a fan. Via burner change in blown burner boilers fuel type can be changed easily. Along with the dual fuel (diesel and natural gas) burners there are also single, two and three stage and modulation burners. In central heating systems two and three stage burners should be definitely preferred. Single stage bruners can be preferred for the small capacity (below 70 kW).

 

Natural Draught Burner Boilers

These boilers burns only natural gas and LPG. They do not work with liquid fuel (fuel oil, diesel). They work quiter compared to blown burner. Their capacity is limited (max 350.000 kcal/h). These kind of burners are designed and sold with the boiler. In this system burner is very important for combustion space and flue adaptation. When you choose a natural draught burner boiler have your existing flue checked by the implementing company and have a guarantee for the adaptation of the flue.

 

Condensing Heating Boilers
Water vapour in the flue gas condenses in the boiler and affects the life of the boiler negatively therefore it is tried to be prevented. So water vapour and flue gas are disposed to the atmosphere from the flue. But this water vapour carries energy and it is not possible to make use of this energy in classic type hot water boilers. At the present type it is possible to make use of this energy. Condensing boilers condense the water vapour in flue gas and decrease the flue gas temperature and gain additional energy. In villa applications there are also pinup types up to certain capacity.

Oven – Water Heater

The advantages of natural gas in kitchen and hot water usage is quite high compared to tube and electricity. First advantage is the high price difference. Natural gas is 80% cheaper than LPG and 70% electricity. On the assumption that people consume 2 tubes for kitchen and hot water in a month one household can save between 110-130 TL. Of course this comfort has a cost. Especially in the central heating buildings simpler and cheaper installations can be used. It requires 1400-1800 TL investment according to the water heater brand and model including installation, project, natural gas water heater. This investment redeems itself between 12 or 18 months. If you pay the cost on credit you can pay the installation cost from the amount that you save from tube cost. Using natural gas in the kitchen does not only help financially, it also help you to cook more delicious. Burning behavior of natural gas spreads into a wider place under the saucepan and it helps food to cook with a more equal heat distribution and more delicious. You can apply to the nearest Izgaz certified company for this comfort.