Electronic Expansion Valves (EEV) w/ Jamie Kitchen

HVAC School - For Techs, By Techs

Bryan Orr

Training, Careers, Airconditioning, Self-improvement, Hvac, Business, Education, Refrigeration, Heating, Ac, Apprenticeship

4.8 • 985 Ratings

🗓️ 27 September 2017

⏱️ 60 minutes

🔗️ Recording | iTunes | RSS

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Summary

In today's podcast, Bryan and Jamie talk about the electronic expansion valve (EEV). Bryan and Jamie describe how EEVs work and the reason they exist. In the process, the hosts also review a wide range of metering devices. We made this podcast to address the rising demand for EEVs in the aftermarket element of the HVAC business.

Like the TXV, the EEV is a metering device. Metering devices create a pressure drop as refrigerant moves from the liquid line to the evaporator. Traditional refrigerators typically use capillary tube metering devices because they require a constant temperature and operate in a fixed temperature environment. However, TXVs are a bit more variable but open linearly and are dictated by a minimum stable superheat value. EEVs are also variable, but they can influence the superheat more directly; the superheat always exceeds the minimum stable superheat. Therefore, EEVs can increase efficiency by reducing the evaporator temperature and compression ratio by increasing saturation temperature.

Even though EEVs dominate the grocery refrigeration market because of their head pressure control, we can use them in residential HVAC too. The EEV controls superheat more precisely than a TXV, and their algorithms can maximize efficiency and fill the evaporator coil with the most refrigerant possible.

There are two types of EEVs: the pulse-width EEV and the stepper motor EEV. The stepper motor has "steps" to modulate the degree to which it opens or closes. The pulse-width EEV either opens or closes, much like a solenoid valve.

Bryan and Jamie also discuss:

Hot pull down
Ideal compression ratios and efficiency
Minimum stable superheat
Compressor cooling accessories
Downsides of oversizing TXVs
Evaporator superheat vs. suction superheat
Technological advancements for EEVs, especially for Danfoss EEVs
Less obvious advantages of EEVs over TXVs

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Transcript

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0:00.0	The free training provided by the HVAC School Podcast is made possible because of the generous support from our sponsors.
0:14.3	Testo, Rector Seal, and Carrier.
0:18.1	Testo is celebrating 60 years of high quality instrumentation with their best in
0:29.2	class fall combustion analyzer promotion. There's never been a better time to get a high quality
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0:50.6	You can get that meter for free if you purchase the Testo 320 or 330 series of
0:54.7	combustion analyzers or you can get a 745 non-contact voltage sensor if you
0:59.9	purchase the Testo 310. This is a limited time offer and you can find out more by going to
1:04.7	HVACR School.com forward slash fall promo which will take you to the testo site where
1:10.4	you can get the form to fill out. You do need to hold on to your receipt from whoever you purchased the combustion analyzer from, but of course we suggest if you don't have a local supplyhouse that stocks these you can easily go to true tech tools
1:23.3	dot com and use the offer code get schooled and you'll get an additional 8%
1:29.5	off then just save your receipt that you get from TrueTech Tools.
1:33.0	Go to HVACR School.com
1:35.0	forg slash fall promo and fill out the form
1:38.0	and you will get either a free 770-3 meter
1:41.0	or a 745 non-contact voltage sensor from Testo.
1:45.8	Testo, 60 years of excellence.
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2:06.8	Discover how ZoomLock can help you be more efficient and productive.
	...

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