SOLAR-DHW, Radiant heating, Thermal storage & bioler controller ?

[rehvacr 0]

This might be lengthy but I believe this is a needed controller. Please help! As the implementation of more and more solar thermal panel are being installed. I see a need to try to collect as much energy as possible for DHW, Radiant floor heating (with thermal mass), water heat storage or collecting heat during the summer to creating a solar thermal flywheel under the living space, if ground water is not present. Having the ability to customize the controller and set priority levels is very important. I have searched the Internet and I do not believe such a controller exists. Sure you can piece micro PLCs together but the main core CPU I/Os are not utilized and the cost goes up with each I/O expansion card/MOD. The core controller/PLC needs to be temperature input and relay output based so In small installation such controllers would not be over kill or over priced. As heating systems evolve with solar collection, GSHP, wood fired boilers and new HHO technology, the need to automate the controller to switch to whatever energy source that will give the biggest bang for the buck automatically is long over due. As far as my own knowledge, I have been in the Electrical & HVACR field for over 20 yrs. and currently an Electrical, Refrigeration & HVAC contractor in two states. (ID & WY) I received My Associate Degrees in Refrigeration, Electrical and Instrumentation Technologies in 1992. I am trying to design or find a LOW COST programmable controller/PLC that will utilize the most solar thermal heat from the collectors as possible or from what ever heat source is available (wood fired boilers, GSHP ...). My controller wish list is at the end of this page. I will try to explain my own building setup as best as I can. Construction is 95% complete. the remaining 5% will be completed when I die or sell which ever comes first! I am currently monitoring my building with a Web Energy Logger (1-Wire based) that can be viewed at http://welserver.com/WEL0064/ Most sensors are in place but some of the sensors are not connected and/or programmed into the WEL yet. This site will show you the heat collection and heating design of the building (~3500 sq ft), it will also show daily, weekly, 30day & 10week charts, setup for data collection that I am looking for. This too is a work in progress. The solar collectors are under the metal roof using warm boards to collect the heat (some what my own design). The 1600gal tank is under ground with ~3ft of sand around the tank, 2 layers of 2” blue board beyond the sand creating a well insulated thermal storage area and a pond liner over the top to prevent rain/snow from washing away the stored heat. The boiler is a 150,000 BTU modulating LP boiler (WelMclain Ultra150) with outdoor rest. The heat exchangers are a brazed plate design, rated at 300,000 BTU/Hr All areas have 5” to 6” of concrete with pex tubing During the winter the snow needs to be cleared off the roof system. This can be done by energizing the upper most roof zone (UC1), because the snow tends to slough down from the peak just after it snows, then staging the lower zones (UC2, LC1 & LC2). So far this has been done manually and works very well, but this needs to be automated & stage the pumps sequentially. I am currently controlling the roof system with a A-19 temp controll that monitors the air temp in the (UC1) Upper collector air space. When the air space reaches ~ 80+ °F it will turn on all collector pumps (P1-P4) and a relay at the boiler. The relay is designed to change to boiler outdoor rest to simulate an out side air temp of 68 °F no mater what the out door temp is. This will ramp down the set point of the boiler from 120+ °F to ~70 °F allowing heat from the collector to be utilized in the building. I am also using a differential temp control with monitoring points located at the outlet of the solar collector and the top of the hydraulic loop of the boiler to turn on circ pumps (P5 & P7). This works well to get the heat into the building. I will come back to the problem in a minute. I think you need to know the heating design and needs of the building The building is insulated VERY well. All zones have their own T-stats, the office area zones are set at 66 °F, and shop area is set at 55 °F. The DHW is an indirect water heater with a set point of 75 °F maintained by the boiler with an electric on demand (set point at 115 °F) in series with the outlet of the indirect water heater to supply hot water to the build. The reason the set point is at 75 °F? Two reasons: first an electric on demand water heater only has a 35°F to 45°F temperature rise capability; the ground water in this area is ~ 50 °F. Secondly this will allow the most solar heat gain possible year round.(collectors turn on at 80°F) If the solar can heat the water temp from 75 °F to 130°F or any where in between you are $ ahead. You have to remember that solar is a supplement to a heating system. The trick is to utilize the heat the best you can, when you can! The problem that I am having is that not all of the energy is being used as best as it can. On a good heat collection days the T-stats do not call for heat all day long, they tend to satisfy around late morning because of the solar gain through windows, so I go around and turn up all the t-stats. If I forget to turn them down, I end up heating the slabs all night long with LP gas to maintain the higher set point. What a waste!!! Most people do not need to/know how to be constantly adjusting their system. Here are some ideas that would make my life easier: The controller needs to be multi Temperature input (4-8) with multiple relay outputs (4-8) The basic controller would have (6) six Temperature inputs and (4) four 3-5amp relay outputs (to run the circ pumps, motors…) Some what easily programmed. PLC ladder logic? Bullion ? GUI w/Basic Programming? Expansion I/O modules to help customize each installation as needed. a. 4-8 temperature sensors (1-Wire, RTD, 10K ohm thermistor, J, K…) b. 2-6 24v to 120v inputs - to detect if something is on c. 6-12 5amp relay outputs – motor, pump … d. Network accessible, Web interface, data logging, email alarms … e. remote reconfiguration Controller priority Wish list: when heat is available 1.clear the roof system of snow if needed to produce max heat gain (staging pumps sequentially) 2.differential temp control to bring heat into the building 3.Heat DHW to with in X degs of ?T (Collector-DHW) or up to 130 °F (what ever comes first) 4.Reset office T-stats from 66 °F to 70+ °F This is VERY important! 5.Reset shop T-stat form 55 °F to 65+ °F 6.send the remaining heat to storage to X °F of ?T (1600 gal tank) 7.retrieve heat from storage to with in X degs of ?T when needed 8.snow melt in concrete aprons when wanted – by pushing a button- when all other priority temps (DHW, Radiant floor & Storage)are met then send any available heat snow melt 9.summer / winter mode to bypass t-stat rest in summer 10.others as needed Any help in finding or help developing such a controller would be greatly appreciated

[entertron 0]

Sir, We might be able to assist you in your application. I have forwarded your information off to my engineer for review. In keeping the solution somewhat modular / configurable, you might want to consider the Smart-PAK PLUS - www.entertron.com/smart-pak.htm Feel free to give us a call to discuss further. Our listed number is 716-772-7216 God Bless,