Boiler Heat Recovery and Energy Savings

Transcription

1 Boiler Heat Recovery and Energy Savings TRUE GREEN SOLUTIONS EcoFlex 90+ System Modulating Fan-Powered Economizer with By-Pass

2 ENERVEX - Quality Energy Savings and Efficiency Over the years, improvements have been made to economizers that now have better heat transfer rates than ever, but it is still only very few boilers that can benefit from their installation. Atmospheric and fan-assisted boilers don t create a powerful draft that can force flue gases through the economizer which make them unsuitable for economizer installations. This changes with the introduction of the modulating fan-powered economizer. With this concept it is now possible to look at a total boiler plant as the load rather than that of the individual boiler. Economizers are usually rated at the maximum load, but in reality this load is rarely achieved. A boiler heating system may operate 3,500 hours per year, but only 10-15% of those hours will be a 100% load, while the remaining hours will average a 40-50% load. In a typical 5,000 MBH atmospheric heating boiler system used in schools, hospitals and hotels/resorts, the radiator design is far more efficient than the traditional economizer over the entire range of load from 20% to 100%. Over 40% more BTU recovery at full load, almost 50% BTU recovery at 60% load down to a little over 30% more BTU recovery at a 40% load. The modulating fan-powered economizer is also significantly more efficient than a traditional economizer in the mid-range load levels. This makes it extremely suitable for most systems and particularly for boiler systems with varying loads. Economical Demand-controlled fan speed promotes energy savings and short term payback Sustainable Exhaust control and heat recovery reduces carbon emissions and wasted thermal energy Efficient Precise function help avoid costly downtime and produces hot water for processing operations Diverse Custom design for several different processing applications and appliances Complete Easily programmed for essential functions and whisper-quiet operation EcoFlex Perfect Exhaust Conditions and Maximum Heat Recovery EcoFlex 90+ System - a packaged modulating fan-powered economizer may be the single design that combats all the challenges in the typical economizer. It opens the energy recovery up to practically any combustion appliance application. With the EcoFlex 90+ System the designer can now view the application as a complete boiler plant as the full load to work with, instead of one economizer per boiler. And the boiler plant can consist of a combination of boiler types such as forced draft boilers and atmospheric water heaters that utilize a single modulating demand-controlled economizer. Single EcoFlex90 + for multiple boilers For atmospheric, fan-assisted, and forced draft boiler or any combination! Variable or constant water flow Easy upgrade, fast payback! And what is even better all boilers will always have the perfect draft conditions due to the variable speed boiler fan controlled by a modulating fan controller. The bottom line is: Design flexibility, reduced emissions, improved boiler efficiency, high return on investment. The variable speed draft fan features a true inline design 2 The pressuredifferential sensor monitors pressure. The constant pressure controller provides the power supply and modulates fan speed. The heat exchanger maximizes heat transfer

3 EcoFlex90 + System Performance... The following tables are examples of the EcoFlex 90+ System s performance when used with Natural Gas. The tables below are based on a boiler system with an elevation of 1019 ft, nominal effiency of 80%, a flue gas temperature at the economizer inlet of 400 F and a water flow of 20 GPM. How to read: 1) Determine your max. exhaust air flow (ACFM) from your system s max. Btu input, 2) go to the blue (Steel) curve to read the corresponding boiler system efficiency (right) after the EcoFlex 90+ System is added and 3) read the corresponding energy recovered (left) MFPE350 MFPE % % Energy Recovered (Btu/h) % 89.0% 88.0% 87.0% 86.0% 85.0% F represents temp. of water in 84.0% Volumetric Flow Rate (CFM) Resulting Boiler Efficiency (%) Energy Recovered (Btu/h) % 89.0% 88.0% 87.0% 86.0% 85.0% 84.0% Volumetric Flow Rate (CFM) Resulting Boiler Efficiency (%) MFPE500 MFPE % % Energy Recovered (Btu/h) % 87.0% 86.0% 85.0% 84.0% 83.0% Volumetric Flow Rate (CFM) Resulting Boiler Efficiency (%) Energy Recovered (Btu/h) % 86.0% 85.0% 84.0% 83.0% 82.0% Volumetric Flow Rate (CFM) Resulting Boiler Efficiency (%)

4 Energy and Operating Savings Ultra Short Payback with Great ROI! There are many ways of taking advantage of the EcoFlex 90+ System s ability to recover energy, save installation cost, and reduce emissions. Below are examples of possible savings. Sabormex - Puebla, MX The two typical system examples both consist of 2 x 1,500MBH and 2 x 750MBH atmospheric boilers 2 with draft hoods and 2 with barometric dampers. The systems operate 4,000 hours per year 600 hrs at full capacity, 2,000 hrs at 50% capacity and 1,400 hrs at 25% capacity. Georgetown Brewery - Seattle, WA Less than 1 year Payback! Less than 2.5 years Payback! Sabormex desired a practical solution to save money and energy with their current 200HP Natural Gas Boiler. The boiler was extensively used to provide hot water for their food processing needs. This resulted in a significant amount of waste heat lost. Georgetown Brewery sought a cost effective solution for adding boiler capacity during the performance of periodic cleaning of their brewing equipment. Their initial intent was to purchase a replacement boiler, but this quickly became cost prohibitive. Given the operating conditions of the boiler, ENERVEX calculated that the Modulating Fan Powered Economizer (MFPE620) was the appropriate application to obtain Sabormex s desired outcome. Sabormex plans to integrate similar applications to more of their factories boilers after seeing the savings with ENERVEX products. Georgetown Brewery utilized the Modulating Fan Powered Economizer (MFPE) for a singular process; therefore constant usage was not required. ENERVEX s extensive experience in the boiler draft industry provided a simple solution that allowed the flue gases to simply bypass the MFPE when there was no demand. System Fuel Type Load Burner Input Exhaust Flow Rate Exhaust Temp In Exhaust Temp Out Water Flow Rate Water Temp In Water Temp Out Total Heat recovered Heat Saved System Fuel Type Load Burner Input Exhaust Flow Rate Exhaust Temp In Exhaust Temp Out Water Flow Rate Water Temp In Water Temp Out Max Heat Reovery Rate Max Heat Energy Saved Full Load Natural Gas 8,760 hrs/year 8,270MBH 3,764 CFM 406 degf 178 degf 14 GPM 77 degf 139 degf 434,502 Btu/hr 525,644 Btu/hr ( therm) The net savings are estimated to (at $0.65 per Therm): Full Load Overall system cost $28,000 Annual savings less Fan power consumption $29,930 Payback 11 months Full Load Natural Gas 2,190 hrs/year 2,500 MBH 1,337 CFM 318 degf 239 degf 25 GPM 154 degf 162 degf 99,780 Btu/hr 261,073 Mbtu/yr* The net savings are estimated to (at $0.80 per Therm): Full Load Overall system cost $5,000 ($25,000 energy grant awarded) Annual savings less Fan power consumption Payback *Based on 83.7% Boiler Efficiency $2, months

5 EcoFlex The Complete System Overview The main system component is a true inline high-temperature, variable speed exhaust fan (TDF) with an integrated heat recovery module (VHX) and EBC35 Exhaust Rate Controller. Both the fan and the heat recovery module is made in 316L stainless steel, so it can be used with virtually any type of exhaust application. Together, the components support design flexibility, reduced emissions, improved heat recovery and high return on investment in a short period of time. The VHX and TDF can be supplied with a tapered inlet and a straight outlet or with tapered inlet and outlet which allows diverse configurations in a vertical and/or horizontal layout. Configuration #1 TDF fan attached to the mating bolt flange on VHX. Configuration #2 TDF fan located elsewhere from VHX in the chimney system including at the termination. TDF Power Venter True In-line Draft Solution The TDF Power Venter is an efficient, high temperature ventilator with backward-inclined impeller. It can be installed horizontally or vertically in a chimney system. The TDF Power Venter is intended for use as a true in-line draft inducer. It is specifically designed for applications where reliable and efficient operation, low noise level, low energy consumption, variable speed and compact design are of utmost importance. The fan housing is equipped with an energy-efficient, totally enclosed, variable speed motor, which is mounted outside the air stream. The motor and impeller are a complete assembly (drive unit) that can be removed from the fan housing without removing the fan from the stack system, allowing simplified repair. *Energy saving EC motors are available as an option. 3

6 VHX Heat Exchanger High Capacity Economizer The Vortex Heat Exchanger, Model VHX, is a revolutionary economizer that addresses the real world need for an efficient economizer with a built-in bypass. The heat exchanger is mounted on an internal rail system that allows it to easily slide in and out for service or cleaning. With its construction in 316L stainless steel, it can be used for both condensing and non-condensing applications. Removeable heat recovery unit sliding on guide rails OUT By-pass damper actuator Maximum Heat Transfer Cooled By-pass exhaust damper By-pass damper in open position The heat exchanger is of a radiator design and is placed at the fan inlet where it covers the entire inlet area for maximum heat transfer. As a result, the system has substantially more heat transfer area than traditional economizers, yet takes up a lot less space. Hot exhaust Available for boilers up to 1,000HP (36,000 MBH) and for oven and other applications with exhaust rates from 1,000 CFM up to 30,000 CFM. For optimal performance the fan speed can be controlled by a modulating pressure control (EBC 30/35). IN The VHX can be used for a variety of applications: Single or multiple boilers Forced draft or atmospheric boilers Condensing or non-condensing boilers Baking Ovens Process Applications Other exhaust applications with high-temperature air By-pass damper in open position Hot exhaust Cooled exhaust By-pass damper in open position Hot exhaust EBC35 Exhaust Fan Controller Automated Fan Modulation This controller monitors the oven draft rate and automatically modulates the fan speed so the ovens experience perfect draft. This control alone can improve a baking system s efficiency with a few percentages. In addition, the control s safety functions make sure the baking system shuts down in case of fan or economizer failure as required by code. By-pass damper in open position Hot exhaust The single point control can also send and receive a variable signal for a variable speed pump. If desired, the controller can coordinate the flow of water based on the temperature of the water passing through the economizer. This coordination allows for a much tighter and consistent delta tee, which means the load can be shed more reliably and utilized more effectively.

7 Any way You Want it! The EcoFlex90+ System concept is a huge leap forward for the energy and cost conscious engineer and building owner. It is possible to install the heat recovery unit in virtually any boiler system new installation or retrofit, single or multiple appliances, modulating or on-off boilers, condensing or non-condensing boilers. System consisting of multiple atmospheric water heaters. The EcoFlex 90+ System is installed inline in the vertical section but could also have been installed in the horizontal section. System consisting of an existing forced draft boiler and an atmospheric water heater. The EcoFlex 90+ System is installed inline in the common horizontal section but could also have been installed in the vertical section. System consisting of multiple forced draft boilers. The EcoFlex 90+ System is installed inline in the common vertical section but could also have been installed in the horizontal section and it could have been sidewall vented. System consisting of multiple atmospheric water heaters. The EcoFlex 90+ System is installed inline in the horizontal section allowing the system to be sidewall vented and save space and venting material Individual economizers are less cost-effective Most economizers serve a single boiler. If only one boiler and economizer is operating, other economizer used for lead-lag or redundancy can t provide any savings which has a major effect on the return of the investment. The lack of a modulating fan also makes the system more prone to operating in-effiencies and operating problems.

8 System Examples The diagrams below show some of the typical applications where the EcoFlex 90+ System can be utilized: Preheating Hot Water Return Preheating Boiler Make Up Water VHX VHX CW In BOILER CW In BOILER HW In Pump Gate Valve Pressure Relief Valve Thermometer Pump Gate Valve Pressure Relief Valve Thermometer Preheating Steam Boiler Feedwater Preheating Circulating Make Up Water VHX VHX BOILER To Existing Boiler Feed System BOILER CW In Feedwater Tank CW In Feedwater Tank Pump Gate Valve Pressure Relief Valve Thermometer Pump Gate Valve Pressure Relief Valve Thermometer Warranty 2 year factory warranty 10 year warranty against corrosion perforation. Contact ENERVEX Next time you design a boiler or water heater system for a project, contact us for a non-binding venting design proposal. In most cases we can offer you a better and less expensive solution. Made By Experience ENERVEX combines quality components, superior technology and experienced personnel to deliver a system that is economical environmentally sustainable, aesthetically pleasing and reliable. Our custom engineering and space saving designs ensure that the project meets code requirements, as well as the high standards of today s architects, engineers and contractors. We don t build a one-size-fits-all draft system - we understand each project is unique. ENERVEX Inc Bluegrass Lakes Parkway Alpharetta, GA USA P: F: T: info@enervex.com