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</o:shapelayout></xml><![endif]--></head><body lang=EN-GB link="#0563C1" vlink="#954F72" style='word-wrap:break-word'><div class=WordSection1><p class=MsoNormal><span style='mso-fareast-language:EN-US'>Hi David,<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'>Yes. Exactly. Dehum is also a good use-case as well, requiring simultaneous cooling and heating – which the heat pump gives.<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'>At the bottom of <a href="https://www.konvekta.ch/network-recovery-systems.html">https://www.konvekta.ch/network-recovery-systems.html</a> “Konvekta uses the DOE-2 building simulation software as a basis to design an energy recovery system.”.<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'>In terms of buildings, I was actually presenting this as a bit of a “blue sky” option for some older hospital estates that we’re doing some front end strategy work for. Many of the current systems use RAR coils. However, most have no heat recovery at all and we’re considering how to retrofit it without reworking duct routes to accommodate S&E air-handlers with plate heat recovery.<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'>I’ve seen this kind of system on laboratory jobs more recently, but not in hospitals or in a retrofit context.<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'>Kind regards<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'>Chris<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=MsoNormal><b><span lang=EN-US>From:</span></b><span lang=EN-US> David Eldridge <DEldridge@grummanbutkus.com> <br><b>Sent:</b> 19 January 2021 03:06<br><b>To:</b> chris.malcolm.yates@gmail.com; 'Jim Dirkes' <jvdirkes2@protonmail.com>; bldg-sim@onebuilding.org<br><b>Subject:</b> RE: [Bldg-sim] exhaust air liquid heat recovery loop<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span lang=EN-US>Chris, I’m sorry I didn’t quite understand your scenario before. Something like this, except it would be a heat pump to make hot and cold<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><a href="https://www.konvekta.ch/integrated-chiller.html">Integrated Chiller - Konvekta AG</a><o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>We’re primarily seeing the runaround type or plate-and-frame direct heat exchange instead of using a heat pump to boost the temperatures, although I can see some appeal.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>What type of buildings are you looking at this for?<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>David<o:p></o:p></span></p><div><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><b><span lang=EN-US style='color:#1F497D'>David S. Eldridge, Jr.</span></b><b><span lang=EN-US style='color:#244061'>, P</span></b><b><span lang=EN-US style='color:#1F497D'>.</span></b><b><span lang=EN-US style='color:#244061'>E</span></b><b><span lang=EN-US style='color:#1F497D'>.</span></b><b><span lang=EN-US style='color:#244061'>, BEMP, BEAP, HBDP, GGA</span></b><span lang=EN-US><o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>Associate</span><span lang=EN-US><o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:4.0pt;color:#1F497D'> </span><span lang=EN-US><o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#365F91'>Direct: (847) 316-92</span><span lang=EN-US style='color:#1F497D'>24</span><span lang=EN-US style='color:#365F91'> | Mobile: (</span><span lang=EN-US style='color:#1F497D'>773</span><span lang=EN-US style='color:#365F91'>) </span><span lang=EN-US style='color:#1F497D'>490</span><span lang=EN-US style='color:#365F91'>-</span><span lang=EN-US style='color:#1F497D'>5038</span><span lang=EN-US><o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;color:#1F497D'> </span><span lang=EN-US><o:p></o:p></span></p><p class=MsoNormal><b><span lang=EN-US style='color:#244061'>Grumman/Butkus Associates</span></b><span lang=EN-US style='color:gray'> </span><span lang=EN-US style='color:#365F91'>| 820 Davis Street, Suite 300 | Evanston, IL 60201</span><span lang=EN-US><o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:9.0pt;color:gray'>Energy Efficiency Consultants and Sustainable Design Engineers</span><span lang=EN-US><o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US><a href="http://grummanbutkus.com/"><span style='font-size:9.0pt;color:gray'>grummanbutkus.com</span></a></span><span lang=EN-US style='font-size:9.0pt;color:gray'> | </span><span lang=EN-US><a href="http://grummanbutkus.com/blog"><span style='font-size:9.0pt;color:gray'>Blog</span></a></span><span lang=EN-US style='font-size:9.0pt;color:gray'> | </span><span lang=EN-US><a href="https://www.facebook.com/pages/GrummanButkus-Associates/1385285015032526"><span style='font-size:9.0pt;color:gray'>Facebook</span></a></span><span lang=EN-US style='font-size:9.0pt;color:gray'> | </span><span lang=EN-US><a href="https://twitter.com/grummanbutkus"><span style='font-size:9.0pt;color:gray'>Twitter</span></a></span><u><span lang=EN-US style='font-size:9.0pt;color:gray'><o:p></o:p></span></u></p></div><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=MsoNormal><b><span lang=EN-US>From:</span></b><span lang=EN-US> Bldg-sim <<a href="mailto:bldg-sim-bounces@lists.onebuilding.org">bldg-sim-bounces@lists.onebuilding.org</a>> <b>On Behalf Of </b>Chris Yates via Bldg-sim<br><b>Sent:</b> Monday, January 18, 2021 6:29 AM<br><b>To:</b> 'Jim Dirkes' <<a href="mailto:jvdirkes2@protonmail.com">jvdirkes2@protonmail.com</a>><br><b>Cc:</b> <a href="mailto:bldg-sim@lists.onebuilding.org">bldg-sim@lists.onebuilding.org</a><br><b>Subject:</b> Re: [Bldg-sim] exhaust air liquid heat recovery loop<o:p></o:p></span></p></div></div><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal>Hi Jim,<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>In a generic sense, this is one of a number of different systems that capture exhaust heat via a coil in the exhaust. In the list below I am trying to establish if anybody has <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><b>Similar systems<o:p></o:p></b></p><p class=MsoNormal><o:p> </o:p></p><ol style='margin-top:0cm' start=1 type=1><li class=MsoListParagraph style='margin-left:0cm;mso-list:l1 level1 lfo3'>We’ve already seen run-a-round coils described<o:p></o:p></li><li class=MsoListParagraph style='margin-left:0cm;mso-list:l1 level1 lfo3'>Exhaust air heat pumps have been a very common system for residential. They tend to use the refrigerant as the heat transfer medium. Some manufacturers of these units are :<o:p></o:p></li><ol style='margin-top:0cm' start=1 type=a><li class=MsoListParagraph style='margin-left:0cm;mso-list:l1 level2 lfo3'><span lang=EN-US><a href="https://www.ivprodukt.com/products/home-concept-ecoheater"><span lang=EN-GB>https://www.ivprodukt.com/products/home-concept-ecoheater</span></a> </span><o:p></o:p></li><li class=MsoListParagraph style='margin-left:0cm;mso-list:l1 level2 lfo3'><span lang=EN-US><a href="https://www.nibe.eu/en-eu/products/heat-pumps/exhaust-air-heat-pumps/NIBE-F750-_-237"><span lang=EN-GB>https://www.nibe.eu/en-eu/products/heat-pumps/exhaust-air-heat-pumps/NIBE-F750-_-237</span></a></span><o:p></o:p></li></ol><li class=MsoListParagraph style='margin-left:0cm;mso-list:l1 level1 lfo3'>Supply and extract air handling with integrated heat pump augmenting (straddling) a plate or wheel heat exchanger. They tend to use the refrigerant as the heat transfer medium. Some manufacturers of these units are :<o:p></o:p></li><ol style='margin-top:0cm' start=1 type=a><li class=MsoListParagraph style='margin-left:0cm;mso-list:l1 level2 lfo3'><span lang=EN-US><a href="https://www.genvex.com/en/products/air-ventilation---air-heat-pump/premium-preheat-500"><span lang=EN-GB>https://www.genvex.com/en/products/air-ventilation---air-heat-pump/premium-preheat-500</span></a></span><o:p></o:p></li><li class=MsoListParagraph style='margin-left:0cm;mso-list:l1 level2 lfo3'><span lang=EN-US><a href="https://www.youtube.com/watch?v=hzVOTjH_GIg&feature=emb_logo&ab_channel=Fl%C3%A4ktGroup"><span lang=EN-GB>https://www.youtube.com/watch?v=hzVOTjH_GIg&feature=emb_logo&ab_channel=Fl%C3%A4ktGroup</span></a></span><o:p></o:p></li></ol></ol><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><b>The system I’m describing<o:p></o:p></b></p><p class=MsoNormal>The heat transfer medium is water or brine (like the RAR coil), but this is piped to a compressor remote from the AHU. The attached is a crude mock-up of such a system using IDA’s ESBO interface (this has not been validated). Apart from a gas boiler for top-up heating, it would be an “all-electric” system. Britain and Scandinavia both have relatively low carbon electricity now. The fact that recovered heat can be re-used in a very general purpose way at a potentially high COP is quite an attractive idea. We may even pre-heat service hot water. Note also that the sum of UA for all the heaters in the zones will be much bigger than the heater coil’s UA in the AHU itself (meaning supplied heat can be a lower grade). It may also remove some of the perceived penalties of reheat (i.e. heat pumps simultaneously make both cold and heat).<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I’m searching for an appropriate quote…<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><i>There are two major products that came out of Berkeley: LSD and UNIX. We don't believe this to be a coincidence.<o:p></o:p></i></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Cheers<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Chris<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><div style='border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=MsoNormal><b><span lang=EN-US>From:</span></b><span lang=EN-US> Jim Dirkes <<a href="mailto:jvdirkes2@protonmail.com">jvdirkes2@protonmail.com</a>> <br><b>Sent:</b> 15 January 2021 21:44<br><b>To:</b> <a href="mailto:chris.malcolm.yates@gmail.com">chris.malcolm.yates@gmail.com</a><br><b>Cc:</b> <a href="mailto:bldg-sim@lists.onebuilding.org">bldg-sim@lists.onebuilding.org</a><br><b>Subject:</b> Re: [Bldg-sim] exhaust air liquid heat recovery loop<o:p></o:p></span></p></div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal>Chris,<o:p></o:p></p></div><div><p class=MsoNormal>I don't think I understand the system....<o:p></o:p></p></div><div><p class=MsoNormal>That clearly means it's not something common for my portion of the world!<o:p></o:p></p></div><div><p class=MsoNormal>On the other hand, it sounds no different than energy recovery - can you clarify a bit, please?<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><div><p style='margin-bottom:6.0pt'><span style='font-size:10.0pt;color:#333333;background:white'>… The world is having a crisis of reason. I don’t think the world is having a crisis of faith. If anything, there is plenty of faith around, in both good and bad things. In some ways, there is altogether too much faith, and too little reason.</span><o:p></o:p></p><div><p class=MsoNormal><span style='font-family:"Arial",sans-serif;color:#222222;background:white'>Jim Dirkes 1631 Acacia Drive NW Grand Rapids, MI 616 450 8653</span><o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div></div><div><p class=MsoNormal><o:p> </o:p></p></div></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐<o:p></o:p></p></div><div><p class=MsoNormal>On Friday, January 15, 2021 8:39 AM, Chris Yates via Bldg-sim <<span lang=EN-US><a href="mailto:bldg-sim@lists.onebuilding.org"><span lang=EN-GB>bldg-sim@lists.onebuilding.org</span></a></span>> wrote:<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><div><p>Hi all,<o:p></o:p></p><p> <o:p></o:p></p><p>I will resist the temptation to say “happy” new year. Perhaps, for 2021, the expression “moderately relieved” new year is more appropriate (it’s certainly more British). I hope as many of you as possible have avoided covid. I know there are some members of this list who have not been so fortunate. God speed your recovery.<o:p></o:p></p><p> <o:p></o:p></p><p>In IDA ICE, there is an option to model a liquid heat recovery loop in the exhaust of an air handling unit (image attached). In essence, this is just putting a cooling coil in the exhaust. Heating, including heat recovery, is after all as much a cooling process as it is a heating process. This cooling coil can then integrate with some form of heat recovery/ reversible chiller – a bit like a run-a-round coil heat recovery on steroids!<o:p></o:p></p><p> <o:p></o:p></p><p>This works in theory. However, I was just wondering how prevalent it is in practice. Would I be naïve to present this as an option to clients? I know I’ve not come across this in the UK. Is it just a Scandinavian thing?<o:p></o:p></p><p> <o:p></o:p></p><p>I’d be very grateful to hear of any projects that have successfully (or unsuccessfully!) integrated heat recovery via exhaust air liquid loops.<o:p></o:p></p><p> <o:p></o:p></p><p>It seems to me that the benefits could be manifold:<o:p></o:p></p><ul type=disc><li class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l2 level1 lfo7'>“decoupling”: Heat recovery potential increases as the building gets warm, but with traditional plate or thermal wheel heat recovery the demand for it simultaneously decreases. By buffering the heat to water, or re-directing it elsewhere (e.g. SHW) heat recovery becomes more general purpose.<o:p></o:p></li><li class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l2 level1 lfo7'>A useful load for the chiller during periods of low chiller load. There are well understood problems with chillers cycling on/off during periods of low load – aka “low delta T syndrowm”. By dual purposing chiller equipment for heat recovery, it provides a stable baseload for chillers during these periods.<o:p></o:p></li></ul><p> <o:p></o:p></p><p>Kind regards<o:p></o:p></p><p> <o:p></o:p></p><p>Chris<o:p></o:p></p></div></blockquote><div><p class=MsoNormal><o:p> </o:p></p></div></div></body></html>