{"id":19015,"date":"2024-03-22T09:07:29","date_gmt":"2024-03-22T08:07:29","guid":{"rendered":"https:\/\/mag.ebmpapst.com\/en\/?p=19015"},"modified":"2024-03-22T09:07:31","modified_gmt":"2024-03-22T08:07:31","slug":"gas-air-ratio-for-hydrogen-cleaneco-sense","status":"publish","type":"post","link":"https:\/\/mag.ebmpapst.com\/en\/industries\/heating\/gas-air-ratio-for-hydrogen-cleaneco-sense_19015\/","title":{"rendered":"Gas\/air ratio for hydrogen: a flex\u00adible system for eco-friendly heating"},"content":{"rendered":"\n

If the inter\u00adna\u00adtional commu\u00adnity is to succeed in stop\u00adping climate change or at least slowing it down, the heating sector will need to massively reduce its CO2<\/sub> emis\u00adsions. Effi\u00adcient boilers and eco-friendly fuels such as hydrogen can play an impor\u00adtant role in this. The regu\u00adla\u00adtions vary from country to country, but in Europe it appears that in future, it will only be permitted to install appli\u00adances that can in prin\u00adciple also run entirely on hydrogen. <\/p>\n\n\n\n

In Great Britain, the plan is to already imple\u00adment this by 2025, and there is also a require\u00adment prohibiting high addi\u00adtional costs during the changeover. Today, new condensing units can already be oper\u00adated with 20 to 30 percent hydrogen, but a mass-market gas\/air ratio control system for the combus\u00adtion process has not been avail\u00adable so far for oper\u00ada\u00adtion with 100 percent hydrogen.<\/p>\n\n\n\n

Optimum air\/fuel ratio<\/h2>\n\n\n\n

As a general rule, the combus\u00adtion of hydrogen is no different to the combus\u00adtion of other types of gas \u2013 the condensing boiler will only work effi\u00adciently if there is an optimum air\/fuel ratio. This is always the case when the ratio is \u03bb = 1.3. To achieve this reli\u00adably, it is crucial that the compo\u00adnents of the gas\/air ratio control system are perfectly matched. Two prin\u00adci\u00adples have proven effec\u00adtive in this respect: The mechan\u00adical-pneu\u00admatic ratio control system and the elec\u00adtronic ratio control system.<\/p>\n\n\n\n

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ebm-papst in heating tech\u00adnology<\/h4>\n\n\n
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<\/a><\/figure>\n<\/div>\n\n\n

Effi\u00adcient compo\u00adnents & systems: blowers, venturi, valves and auto\u00admatic burner controls from ebm-papst.<\/p>\n\n\n\n

Our solu\u00adtions for different appli\u00adca\u00adtions.<\/a><\/p>\n<\/div><\/div>\n\n\n\n

Both ratio control systems comprise a blower, venturi, gas valve, and burner controls. The most impor\u00adtant differ\u00adence is that, unlike pneu\u00admatic ratio control systems, the gas valve in elec\u00adtronic ratio control systems can be actively controlled. The advan\u00adtage of this is that it is gas-adap\u00adtive and can auto\u00admat\u00adi\u00adcally adapt to the combus\u00adtion mixture. However, these two prin\u00adci\u00adples avail\u00adable on the market are not suit\u00adable for ensuring safe and effi\u00adcient combus\u00adtion if the unit runs entirely on hydrogen.<\/p>\n\n\n\n

Elec\u00adtronic ratio control systems would not work because the hydrogen flame is not conduc\u00adtive and cannot, there\u00adfore, be used as a control vari\u00adable for the ioniza\u00adtion process. In contrast, the estab\u00adlished mechan\u00adical-pneu\u00admatic ratio control system would work in prin\u00adciple, but the only way that the unit could run on hydrogen is with an inef\u00adfi\u00adcient gas\/air ratio. A new system solu\u00adtion is there\u00adfore required.<\/p>\n\n\n\n

A new gas\/air ratio control system: CleanEco Sense<\/h2>\n\n\n\n

With CleanEco Sense, ebm-papst has devel\u00adoped a new oper\u00adating concept that is suit\u00adable for both conven\u00adtional and all-hydrogen oper\u00ada\u00adtion (Fig. 1). Due to the laws of physics, the burner always needs to be replaced when switching over to hydrogen. However, the compo\u00adnents supplied by ebm-papst (including the blower, venturi, gas valve, and burner controls) remain unchanged, meaning the changeover is afford\u00adable for end users.<\/p>\n\n\n\n

Fig. 1: CleanEco Sense oper\u00adating prin\u00adciple: The CleanEco Sense elec\u00adtronic-pneu\u00admatic gas\/air ratio control system comprises an elec\u00adtronic gas valve, the gas blower, venturi, and control unit. The stepper motor in the valve enables the gas quan\u00adtity to be flex\u00adibly adjusted; the blower speed deter\u00admines the volu\u00admetric flow. Intel\u00adli\u00adgent sensors in the valve contin\u00adu\u00adously measure the posi\u00adtion of the stepper motor and the pres\u00adsure. The control unit constantly eval\u00adu\u00adates this measure\u00adment data and can make read\u00adjust\u00adments at any time. For all-hydrogen oper\u00ada\u00adtion, only the burner needs to be replaced.<\/figcaption><\/figure>\n\n\n\n

To create the new concept, the combus\u00adtion special\u00adists at ebm-papst have combined the advan\u00adtages of the mechan\u00adical-pneu\u00admatic and elec\u00adtronic ratio control systems and devel\u00adoped a so-called elec\u00adtronic-pneu\u00admatic ratio control system in which the gas valve can be actively controlled. The tried-and-tested F01 range of elec\u00adtronic gas valves (Fig. 2) is used for this purpose, expanded to include intel\u00adli\u00adgent sensors. The combus\u00adtion behavior of hydrogen was inves\u00adti\u00adgated in detail to enable safe oper\u00ada\u00adtion.<\/p>\n\n\n\n

Hydrogen burns differ\u00adently to natural gas<\/h2>\n\n\n\n

The element is very reac\u00adtive and has a high flame velocity. If it is only mixed in, this is not a problem provided the content is no higher than 30 percent. However, the situ\u00ada\u00adtion changes if the unit runs on 100 percent hydrogen. The greatest risk in this case is \u201cflash\u00adback\u201d, which is when the flame migrates back from the burner toward the gas\/air ratio control system in the oppo\u00adsite direc\u00adtion to the flow, thereby damaging the boiler (Fig. 3). <\/p>\n\n\n\n

This is partic\u00adu\u00adlarly crit\u00adical during the igni\u00adtion process as the flame spreads out very quickly after igni\u00adtion. High pres\u00adsure is produced as a result, meaning new fuel mixture cannot flow into the burner quickly enough. <\/p>\n\n\n\n

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    \n
    Fig. 2: The G02 range of elec\u00adtronic gas valves enables the combus\u00adtion air ratio to be controlled, including in pneu\u00admatic ratio control systems. When combined with the built-in sensors, the unit can, there\u00adfore, run on 100 percent hydrogen.<\/figcaption><\/figure>\n<\/div><\/ul>\n<\/div>\n\n\n\n
    \n
    Fig. 3: The graph shows the flame velocity as a func\u00adtion of the air concen\u00adtra\u00adtion. Hydrogen (green line) ignites much faster than methane (orange line), espe\u00adcially at high concen\u00adtra\u00adtions.<\/figcaption><\/figure>\n<\/div><\/div>\n<\/div>\n\n\n\n

    In turn, when the unit is running, a crit\u00adical state can occur in partic\u00adular when lower outputs are requested. The reason for this is the high flame velocity of the hydrogen \u2013 the flame comes to a stand\u00adstill where the flame velocity is as high as the efflux velocity. At the rated output, this happens at a suffi\u00adcient distance from the burner surface. If the output is reduced, the efflux velocity decreases but the flame velocity remains roughly the same. The distance between the flame and burner reduces and there is a risk of flash\u00adback (Fig. 4).<\/p>\n\n\n\n

    Fig. 4: At full output (a), the efflux velocity and flame velocity are equal. The flame stabi\u00adlizes at a suffi\u00adcient distance from the burner surface. If the efflux velocity at low output (b) is too low, the flame may migrate into the burner and a flash\u00adback may occur.<\/figcaption><\/figure>\n\n\n\n

    Safe igni\u00adtion, safe oper\u00ada\u00adtion<\/h2>\n\n\n\n

    As a result, the key is to master precisely these two aspects. The CleanEco Sense and the built-in intel\u00adli\u00adgent sensors in the elec\u00adtronic gas valve make it possible to prevent flash\u00adback during igni\u00adtion and oper\u00ada\u00adtion.<\/p>\n\n\n\n

    To make the igni\u00adtion safe, the amount of air is adjusted for the brief period of the start-up process in such a way that the reac\u00adtion is less intense. In a conven\u00adtional mechan\u00adical-pneu\u00admatic ratio control system, a fixed setting for the ratio is set once during instal\u00adla\u00adtion using the main flow throttle and it can then no longer be changed during oper\u00ada\u00adtion. However, with the CleanEco Sense it is possible to vary the \u03bb value for the crit\u00adical igni\u00adtion phase. This solves the problem of flash\u00adback during start-up.<\/p>\n\n\n\n

    That then leaves the flash\u00adback during oper\u00ada\u00adtion. To prevent this, it is impor\u00adtant to know the volu\u00admetric flow for the mixture as it enters the burner. In a mechan\u00adical-pneu\u00admatic ratio control system, this can only be roughly esti\u00admated based on the blower speed. However, in order to reli\u00adably prevent flash\u00adback during oper\u00ada\u00adtion, it is impor\u00adtant to precisely control the efflux velocity. <\/p>\n\n\n\n

    \n

    The gas valve of the CleanEco Sense was equipped with intel\u00adli\u00adgent sensors that perma\u00adnently monitor the pres\u00adsure in the system and the posi\u00adtion of the stepper motor. <\/p>\n<\/blockquote>\n\n\n\n

    Both measured vari\u00adables provide infor\u00adma\u00adtion about the quan\u00adtity of gas conveyed. An algo\u00adrithm devel\u00adoped by ebm-papst eval\u00adu\u00adates this data in the control unit and regu\u00adlates the blower speed accord\u00adingly, ensuring that the efflux velocity does not fall below a crit\u00adical level. <\/p>\n\n\n\n

    As a blockage in the exhaust and intake air system can also cause poor air perfor\u00admance, the system checks whether the vacuum gener\u00adated by the blower corre\u00adsponds to the setpoint before igni\u00adtion takes place. If it does not, the safety valve does not open in the first place. As an addi\u00adtional benefit, the smart gas valve also makes it easier to control the combus\u00adtion of natural gas or biogas.<\/p>\n\n\n\n

    High modu\u00adla\u00adtion level, simple to install<\/h2>\n\n\n\n

    Regard\u00adless of the combus\u00adtion mixture, the CleanEco Sense has managed to almost double the modu\u00adla\u00adtion depth of the blower to 1:15. As a result, the boiler output can be adjusted much more precisely to suit the actual demand. This reduces the amount of fuel required, which means lower CO2<\/sub> emis\u00adsions when the unit runs on natural gas. The advan\u00adtage is that this high modu\u00adla\u00adtion depth can be achieved without the manu\u00adfac\u00adturer or installer needing to configure complex settings on site.<\/p>\n\n\n\n

    \n

    The advan\u00adtages of the CleanEco Sense at a glance<\/strong><\/h3>\n\n\n\n
      \n
    • Unit can run on natural gas, biogas, and 100 percent hydrogen<\/strong><\/li>\n\n\n\n
    • To switch over to all-hydrogen<\/strong> oper\u00ada\u00adtion, only the burner needs to be replaced<\/li>\n\n\n\n
    • Simple to install<\/strong> as the system adjusts itself<\/li>\n\n\n\n
    • Short devel\u00adop\u00adment time<\/strong> as stan\u00addard compo\u00adnents are used<\/li>\n\n\n\n
    • Turn-sown ratio of 1:15<\/strong> over the entire output range from 2 to 385kW<\/strong><\/li>\n\n\n\n
    • Fami\u00adlies of gases are auto\u00admat\u00adi\u00adcally detected<\/strong><\/li>\n\n\n\n
    • All compo\u00adnents have been certi\u00adfied for hydrogen oper\u00ada\u00adtion<\/strong><\/li>\n<\/ul>\n<\/div><\/div>\n\n\n\n

      Although the system is not gas-adap\u00adtive, the intel\u00adli\u00adgent sensors make it possible to detect when the combus\u00adtion mixture changes. In such cases, the boiler does not start at all, consti\u00adtuting an addi\u00adtional safety feature. The system has a modular design comprising stan\u00addard compo\u00adnents. <\/p>\n\n\n\n

      ebm-papst\u2019s product port\u00adfolio offers the appro\u00adpriate sizes of blower, venturi, and gas valve to cover the entire output range from 2 to 385 kW, meaning CleanEco Sense is suit\u00adable for both private house\u00adholds and larger commer\u00adcial appli\u00adca\u00adtions. In a nutshell, CleanEco Sense is a future-proof and flex\u00adible system that can play a major role in the energy tran\u00adsi\u00adtion in the heating sector.<\/p>\n","protected":false},"excerpt":{"rendered":"

      If the inter\u00adna\u00adtional commu\u00adnity is to succeed in stop\u00adping climate change or at least slowing it down, the heating sector will need to massively reduce its CO2 emis\u00adsions. Effi\u00adcient boilers and eco-friendly fuels such as hydrogen can play an impor\u00adtant role in this. The regu\u00adla\u00adtions vary from country to country, but in Europe it appears [\u2026]<\/p>\n","protected":false},"author":43,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"wp_typography_post_enhancements_disabled":false,"footnotes":""},"categories":[19,8],"tags":[218,219,220,221],"class_list":["post-19015","post","type-post","status-publish","format-standard","hentry","category-blowers","category-heating","tag-cleaneco-sense","tag-condensing-technology","tag-gas-air-ratio-control-system","tag-hydrogen"],"acf":[],"_links":{"self":[{"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/posts\/19015","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/users\/43"}],"replies":[{"embeddable":true,"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/comments?post=19015"}],"version-history":[{"count":23,"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/posts\/19015\/revisions"}],"predecessor-version":[{"id":19084,"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/posts\/19015\/revisions\/19084"}],"wp:attachment":[{"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/media?parent=19015"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/categories?post=19015"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/tags?post=19015"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}