condensing boiler The condensing boilers are the most modern and environmentally friendly boilers that exist today. Manages to achieve very high efficiency by recovering the latent heat of condensation of water vapor contained in the fumes, as well as emission reductions
nitrogen oxides (NOx) and
carbon monoxide (CO) which can reach 70 % compared to traditional installations.
differences with traditional boilers
Regular boilers, including those defined as "high efficiency" (the yield is on the order of 91-93%, reported the lower heating value), manages to use only a portion of the sensible heat of the flue gas to because of necessity, purely technical (decay boiler), to prevent condensation of gases. The water vapor
generated by the combustion process
(about 1.6 kg per cubic meters of gas) is then dispersed into the atmosphere through the chimney
: The amount of heat it produces, called
latent heat, is well 11% of the energy released by burning but can not be recovered. The condensing boiler, however, can recover a large part of the latent heat content in the flue gas expelled through the chimney. The particular condensing technology makes it possible to cool the smoke until they return to the state of saturated liquid (or in some cases wet saturated steam), with a recovery of heat used to preheat the return water from the plant. In this way the temperature of the gas output (which is lowered to 40 ° C
) always maintains the same temperature value of water supply, well below the then 140 ~ 160 ° C high-efficiency generators and 200 ~ 250 ° C conventional generators.
fumes discharged at low temperature do not allow the natural draft of the chimney and should be deported due to the prevalence of the burner (and fan) of the boiler, so we have a gas line pressure which must be perfectly sealed making it difficult to discharge more boilers in a single stack.
Performance [edit ]
In technical brochures of the various manufacturers of condensing boilers usually state that they achieve returns in excess of 100%. These values, which are physically impossible, do not indicate any violation of the basic principles of
Thermodynamics but follow from a calculation of the performance
deliberately "wrong": it is indeed based on
calorific value of fuel used rather than the gross calorific value
(as it should be done, since there
condensation of water vapor smoke) in order to obtain the values \u200b\u200bthat are homogeneous and therefore comparable with the yields of conventional boilers.
Collection and disposal of condensate [edit ]
Given the low temperature gas condensing boilers can be used in polypropylene flue, the best solution to avoid problems of corrosion of pipes caused by acid condensation. They also need a pipe for condensation water, acid, formed during operation and which conveys that condenses into a separate drip tray (also called the condensate sump
). In particular, the standard UNI 11071 ("Criteria for the design, installation, commissioning and maintenance of household and similar installations that use gas fuel, subservient to condensing boilers and associated services of nominal heat input not exceeding 35 kW ") requires the presence of two disposal facilities: one for removing the condensate from the boiler and to remove a the condensate coming from the exhaust fumes.
regard to the characteristics of the discharged condensate in the collection, you should always refer to UNI 11071, which regulates precisely the characteristics of discharges for boilers with less than 35 kW of power so that they fall within the legal limits set in Decree No. 155/1999 and Decree No. 258/2000 for the discharge to surface waters. UNI 11071
In the following two cases are distinguished:
- installation of a boiler in a room for residential purposes: for civil uses no special precautions are needed since the condensed products thoroughly neutralized by washing and other domestic sewage (such discharge fact have a significant basicity and also have the ability to form deposits in pipes with respect to acid buffer property).
- installation of a boiler in a room for office: if the office, coupled to a single unit, has a number of people under 10, it is advisable to install a condensate neutralizer. In the event that the number of users is greater than 10, the same considerations made for the apartment in a residential installation.
Economic Benefits [edit ]
- savings are achieved in the order of 15 ~ 20% the supply of hot water at 80 ° C, and 20 ~ 30% at 60 ° C.
- performance are best at partial load, or heating a building, where with traditional radiators allow savings of 25 ~ 30%
- uses the highest performance (40% savings and more) when used with systems that operate at low temperature (30 ~ 50 ° C), such as with radiant systems (panels on the ceiling, floor or serpentine serpentine wall).
- When you replace a conventional boiler with a condensing can choose one of lesser power rating. If you complete the system integration of solar panels, and add the savings that comes from the use of solar energy (25 ~ 30% average), you may notice that the combination of solar panels and condensing boilers this can save on the order of 50 ~ 60%.
Firstly, I am very, very expensive. In 2007, it was purchased new toilet for the International Space Station ISS the modest sum of $ 19 million, almost 14 million €. This technological gem is mounted in the enlargement of the station in 2009. The old system of disposal of organic waste had shown signs of slowing down, so that between May and June 2008, astronauts dovunti are staying two weeks with the toilet not functioning due to lack of a spare, almost as it happens in our homes! In fact, the toilet has stopped working and the many attempts to repair have been all in vain. The only solution was to do with sending a new one from the ground. 
