MULCAHY MINUTE GLYCOL IN HYDRONIC SYSTEMS MULCAHY CO. Since 1929

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1 MULCAHY CO. OCTOBER 2009 VOLUME 10, ISSUE 3 MULCAHY MINUTE E N G I N E E R E D F L U I D H A N D L I N G A N D H V A C S O L U T I O N S Since 1929 GLYCOL IN HYDRONIC SYSTEMS Mulcahy added Dow Chemical to our product offering this month. So, we figured an article on how glycol effects chilled and hot water systems would be beneficial! Many people in cold climates such as ours utilize some form of freeze protection in their hydronic heating and cooling system. Mixing a little glycol is a relatively easy thing to do to reduce the freezing point of their system. How the addition of glycol affects a hydronic system however is often misunderstood. Glycol influences heat transfer. A given terminal unit or heat exchanger will lose performance and can increase its pressure drop as the glycol concentration is increased. The effect on a heat exchanger performance will vary with glycol type, concentration, and temperature. Computer selection programs are usually employed to account for the difference in glycol mixtures. Glycol systems will require a greater amount of fluid be pumped to satisfy the identical heating load when compared to pumping pure water. Therefore, for the same BTU we need to increase the flow (remember BTU = ΔT * 500 * GPM). The increase in flow in larger commercial systems because of the addition of glycol can add a significant amount of horsepower to a system. The increase in flow is related strictly to the concentration and type of glycol. Since Glycol systems typically requires pumping more fluid than water; the pressure drop increases (More fluid down the same pipe will increase the pressure drop). However, there is another component that comes into play. The viscosity or thickness of glycol changes greatly with temperature change. Most pressure drop correction charts do not add for glycol mixtures at high temperatures (150 F and up) because the viscosity is roughly the same as water. However, as we drop the temperature of a glycol mixture, the viscosity increases and the extra pressure drop is significant. For example: At 150 F a 40% ethylene glycol mixture will have the same friction loss as a pure water system. However, if you drop the temperature of the system down to about 45 F, the pressure drop increase is about 20%. The system pressure drop increase varies with glycol type, concentration, and temperature. DOW PRODUCTS DOWFROST (PROPYLENE GLYCOL) DOWFROST HD (FOOD GRAD PROPYLENE GLYCOL) DOWTHERM (ETHYLENE GLYCOL) ALL GLYCOLS ARE AVAILABLE IN STRAIGHT GLYCOL OR PRE-MIX (GLYCOL/DI WATER MIXTURE) Glycol also affects system expansion rates. Glycol mixtures expand more than water. The net effect is again related to the concentration and TYPE of glycol used. Ethylene glycol mixtures in a typical system will expand approximately 20% more than water systems. Propylene glycol mixtures will expand approximately 30% more than water. Not accounting for the fact that glycol is being used can easily lead to an undersized expansion tank. A final impact glycol has on a system is fluid quality and is often the most problematic. Glycol brings a certain amount chemical reactivity to a hydronic system. Glycol systems often have a higher rate of pump seal, valve packing, pipe clogging, and etc problems. Overly aggressive chemical treatment often makes the problem worse rather than better. Certain general steps can be taken to reduce the likelihood of a glycol/chemical equipment failure. 1) -Most glycol manufactures recommend de-ionized or distilled water be used to fill the system. 2) - Keep the ph of the system between the limits of the pump seal. Most pumps are rated for a ph between 7.0 and 9.0. Anything outside of those limits and you run the significant risk of early and frequent seal failures. Most manufacturers offer pump seals with a larger ph range. However, the standard range of 7 to 9 works for most glycol systems. DOW offers yearly water analysis on all projects over 250 gallons, talk to your salesperson for details. 3) -Keep the water clean of solids. Particulates in any hydronic system reduce seal life. But in glycol systems the precipitates formed can be small and not as easily detected. Filtration and flushing are often the answer. So always flush properly before adding the glycol. Mulcahy s current availability is 275 gallon totes, 55 gallon drums, 5 gallon containers & compartmentalized tankers.

2 MULCAHY MINUTE I N T R O D U C I N G H A M I LT O N E N G I N E E R I N G Condensing Product Efficiencies at Full Fire % Efficiency What really makes the EVO more efficient than other condensing products? EVO Family Highest possible operating efficiency over the Brand A greatest range of conditions. Many manufacturers have designed, and currently Brand C produce, a product line that will only condense with extremely cold incoming water temperatures, and Brand F while firing at a minimum firing rate. This leaves much of the potential savings for the user of such a Brand P product going where they do with non-condensing products: right up the stack! Why pay for condensing technology if the product won t condense when firing Incoming Water Temperature - F at the full-rated BTU input? That s like leaving 10% of the potential savings right on the table! Hamilton s product engineers have patents on condensing technology dating back to 1974! The EVO line of products carries the highest possible efficiency ratings and has been tested and certified to meet current CSA and ANSI standards. These certifications have been carried out by both our certification agency, Intertek ETL, and by 3rd party labs such as B.R. Laboratories in California. Products from 80,000 BTU/hr to 8,000,000 BTU/hr, using identical technology and design, for water heaters, heating boilers and pool heaters alike. Whether your needs are just domestic hot water, space heating, or both - or even a pool heater - our EVO products are virtually identical, with the exceptions of internal operating software and a few safeties, as required by code. Serviceability Any mechanical product will require some form of service throughout its lifetime, and the entire EVO line is designed for ease of service. All of our products are designed to be serviced by simply opening the cabinet door, never having to remove other jacket panels, venting, wiring or piping. All major components can be accessed or removed within 60 seconds of opening the cabinet, saving you time on maintenance needs when they do arise. Systems Technology Only the Hamilton EVO line can be shipped as a complete, factory-assembled and tested system, with up to 8,000,000 BTU s of input. These custom designed and manufactured arrangements carry the UL 795 and CSA 3.4 certifications, assuring you a properly engineered and assembled system, no matter your application. These assemblies provide you with single point connections for water (incoming and outgoing), condensate neutralizer to drain, gas, electrical intermediate disconnect, as well as exhaust and intake air venting through our common vent manifolds. Companion CWIS (see photo to left) Substantially longer life than any Tank Type Water Heater. Patent pending Cold Water Injection System (CWIS ) assures maximum efficiency possible 100% of the cold water flows through the heater before entering the tank until the recirculation rate has been reached - higher first hour delivery than comparable inputs. Stainless & Glass tanks up to 160 gallons and sizes up to 630 MBH input. The Rack Pack Six Pack Rack Pack Six Pack - the modularity of this redesigned line allows us to ship completely ready to plug & play 1. Cascade Controls 2. All water piping 3. Gas piping, including individual shut offs 4. Condensate drain and neutralizer to one common connection point 5. Venting - one inlet air and one exhaust, no matter how many units are installed! 6. Electrical - individual circuit breakers in a common box 2

3 MULCAHY MINUTE MASON CAN DO IT ALL! As a Mason Representative we receive weekly letters from Norm Mason, owner of Mason-Mercer Industries. Now Norm is well into his 80 s and still working everyday. He began writing HVAC Engineering Specifications in 1962 and if you don t have the VSC Complete HVAC Engineering Specification Bulletin, then let us know! You should! Anyway, back to the letters. Mason writes us as if we were standing right in front of him and each letter (which by the way are still mailed!) are always about some experience he has had. This is the best received information. We d like to share one of these in hopes that the experience may help you now or in the future and for you to understand the magnitude of expertise and engineering marvel Mason Industries can do for you! Mason Expansion Compensator Another Mason representative had a contractor posed with a problem: he was working on a 58 story building and all the hot water supply and return risers as well as the chilled water supply and return risers were copper. The diameters were as small as 3/4 with the largest 3. Since the copper rate of expansion is close to 40% above that of steel, there was a great deal of movement to be taken care of. The problem was first approached by minimizing the movements and setting anchors as little as 7 stories apart. However, if we installed simple expansion joints or housed expansion joints like the Expansion Compensators, the thrust force developed by the area times the pressure exceeded the ability of the thin copper riser walls to resist thrust pressure. They would have buckled. So our fellow representative suggested that rather than using those conventional devises, to do the whole job using copper Vee s. The force required to displace a Vee is only 10% of an expansion joint thrust. Since the anchors were placed relatively close together, there was not a great deal of movement per Vee, so they were able to provide shorter Vee s than the standard 4 movement. This kept the contractor within the limited space requirements. The best part is Mason did all the engineering and supplied the contractor with a detailed piping diagram at NO CHARGE! 3

4 VOLUME 10, ISSUE 3 Example of Mason s Engineering Drawings INSIDE STORY HEADLINE NOT ALL RUBBER CONNECTORS ARE THE SAME Safeflex expansion joints are molded and vulcanized in hydraulic presses. This high pressure process produces a smooth finished product with outstanding adhesion between the cover, reinforcement and tube. Most of our competitors still use Natural Rubber impregnated Nylon tire cord between sulfur cured, EPDM covers and tubes. This construction becomes brittle with age at higher temperatures. We have changed from Nylon to Kevlar, as Kevlar has a higher modulus that minimizes swell and elongation, and outstanding temperature tolerance up to 250 F (121 C).Changing the EPDM curing system from sulfur to the slower, more expensive peroxide method raised the high temperature safety factor, as well as other physical properties. We friction EPDM between and over the Kevlar cords. This makes Safeflex superior as cover, reinforcement and tube are all homogeneous. Natural Rubber has been completely eliminated to improve aging and temperature tolerance. Another serious problem was the body pulling out of the flange because flexible bead wire does not provide sufficient retention. Our answer to this was to wrap the tire cord around a solid steel ring in place of the cable. The steel ring cannot pull through. Sealing pressure is applied through ductile iron flanges that rotate inward around solid exterior stops. The split flanges are hooked together to prevent spreading. Safeflex is the culmination of 25 years of application experience and a driving desire to eliminate all possible failures. These improvements are costly, but the engineering and contracting communities and the consumers they serve have always been receptive to our improved longer lasting and safer products. Why risk failure when there is a better product. 4

5 VOLUME 10, ISSUE 3 AQUATHERM IS APPROVED IN MN MULCAHY 80TH ANNIVERSARY Mulcahy Celebrated it s 80th Anniversary in July with the ABB Roadshow. It was a well attended event with lunch and seminars focused on ABB Variable Frequency Drives. The Roadshow comprised of working demos including: a ULH/Fan Demo; Dyne Demo; Communication Demo; MCC Demo, and Switchgear Demo; these work alongside a host of static displays. Thanks to all those that participated and congratulations to all our winners and to Terry Stofferahn from ATS&R who won the Gourmet Grill! We truly appreciated everyone taking time to enjoy a beautiful day for lunch and education. 5

6 2700 Blue Water Road No. 100 Eagan Minnesota phone fax E N G I N E E R E D F L U I D H A N D L I N G A N D H V A C S O L U T I O N S Mulcahy is excited to introduce Stanley Virax Press Tools. Contact Mulcahy for a participating stocking distributor and/or a demonstration. P20+ M20+ Quick-change inserts handle copper or PEX Interchangeable insert system reduces kit weight, eliminates calibration Mechanical design for easy maintenance Microchip monitors and ensures sufficient power for successful presses Indicator light clearly shows when a successful press has been completed Cycles in four seconds the fastest time on the market 180 head rotation Weighs less than 11 Lbs. 45% more cycles per battery charge than the leading competition 14.4v Li-Ion battery recharges in just 30 minutes Narrow body design for easier maneuverability Fully galvanized jaws reduce copper build-up and prevent rust and corrosion Powerful hydraulic system for maximum power on large diameter Jaw stabilization technology ensures accurate jaw motion Cycles in four seconds the fastest time on the market 360 head rotation Weighs less than 16 Lbs. 14.4v Ni-MH battery recharges in just 60 minutes Full lifetime warranty against manufacturers defects and workmanship