Programmable Automated Controls (PAC) for Integrated Systems

Rod Stucker

I have struggled with finding hardware and software for provision of integrated controls for solar thermal, solar PV, ERV/HRV with ground to air heat exchanger and fan-coils, water to water variable GSHP and desuperheater.



Recently I ran across OPTO 22's SNAP PAC and wireless device technology which they claim can provide the wife acceptance factor (WAF) while allowing for several levels of control for an automated smart home. They can also incorporate a home energy management system.



<a href="http://www.opto22.com/site/snap_pac_system.aspx">http://www.opto22.com/site/snap_pac_system.aspx</a>



<a href="http://www.opto22.com/site/pr_selector.aspx?cid=1&qs=1012">http://www.opto22.com/site/pr_selector.aspx?cid=1&qs=1012</a>



<a href="http://www.opto22.com/site/documents/doc_drilldown.aspx?aid=3960">http://www.opto22.com/site/documents/doc_drilldown.aspx?aid=3960</a>



It seems a little spendy at first, but I haven't found anything else is that is more user friendly and is capable of providing automation of integrated controls for smart homes including sprinklers, all from a home PC or smart device with wireless capability.



The executive summary of the attached PDF provides more detailed information on our need for integrated controls for hydronic-radiant floor heating and cooling of a continuous concrete structure with thermal energy storage, both hot and cold. The oversized fan-coils of the ERV/HRV will regulate humidity and keep the HVAC system above dew point temperature. We are interested in using solar radiation with separate zones for the areas on the south side of the structure that are affected.



Obviously, we would like to use as simple a control approach as possible while being able to coordinate outside temperature and humidity with those on the inside of the structure. For cloudy periods in which we do not have access to solar thermal, the GSHP and desuperheater will provide redundancy. The reversible GSHP will also backup the ERV which will be equipped with fan-coils and provide cool air flush during summer evenings and mornings. We are hoping to optimize use of the high thermal mass of the continuous concrete structure and also the thermal energy storage system.

SWEI

Direct Digital Control

is the industry term for this, and the better systems feature fully programmable everything.



If you hired me to do this, I would use a BACnet platform from http://www.reliablecontrols.com/



If you want to do this yourself, you have a bit of a learning curve ahead of you but there are quite a few options.  You might take a look at http://www.mrpexsystems.com/idc.asp



Assuming you intend to market this system to the public, you will want to simplify both the system design and the controls.  That's not always as easy as you might think, but it is a rewarding process.

Rod Stucker

SNAP PAC vs. BACnet or IDC Platforms

I recognize your comments from my Radiant systems blog.



I am continually intrigued with the number of user friendly automated solutions out there. I am assuming that both BACnet and IDC platforms are user friendly and provide wireless control access including home energy management. I am obviously still in R&D mode, but what makes you recommend these systems? I see that they are ASHRAE compliant if that is the best way to describe them?? Are they capable of providing programmable automated controls of smart homes and energy management in addition to providing integrated HVAC controls?

SWEI

Fully programmable

means that every aspect of their operation is driven by the code you write (or the objects you drag and drop from which the 4GL creates and compiles into something P-code-esque.)  The only real limits to what you can do are driven by available memory and CPU, and what kind of I/O is available.  That would be protocol and communications I/O as well as analog I/O.



An old T87 thermostat would qualify as user friendly, and could well win the design award over something far more complex.  Making modern digital electronics truly user friendly is a high art (and impresses me mightily when I come across it.)



Not sure which blog you refer to, but it's certainly possible I've been there.  The DDC platform I use would qualify as user friendly to a controls integrator, but not to a homeowner.  It needs dedicated development tools and a skilled operator in order to function at all, and is optimized for the HVAC-centric operations typical in commercial and industrial settings.  General purpose home automation is a scary market to me -- far too many big players competing with far too much cash and too many competing "standards" for my taste.



I'm still curious what you're really trying to accomplish here -- if it's truly a packaged systems approach to be sold to (or through) homebuilders, you may want to consider a bit of market analysis before you burn too much of that startup cash.  I'm involved with a couple of groups who are working that way who are spending more effort in finance, building code development, and zoning than any of us would ever have expected.  It's really tough to effect fundamental change to a system this big and this entrenched, and darn near impossible when we underprice energy through a pervasive network of hidden subsidies.