[secureitall]

Hi
I am an alarm engineer with a nacoss gold firm

I have moved house and decided to extend my HA system
I have interfaced my galaxy dimension control panel to my own vb.net Automation app.
This currently takes info from the alarm panel as they happen and responds accordinly.
Id like to add hearing control to this.
I have worked out how to control the boiler by modify a thermostat (its a worcester bosch unit and has a few controls on the stat that i can run from the pc)
But i cant control the rads.
Ideally id like an rf based unit that will screw onto the existing valves. I alo need to get room temp into the app, per room.
I have a total of 9 rooms i need to control.
I have looked at the honeywell system and the househeat units.
problem is i cant see a way to control this via my app.
Ideally id like something with a sdk or at least a .net lib, but even something with a 232 port on it would allow me to control it.
I also plan to replace the lpg combi boiler with a ground source heat pump as funds allow, I doubt its relevant as rad control is rad control.

Many Thanks for any ideas you may have.
James

[neilball]

You will not find radiator controllers that allow direct wireless control, all of the units that I am aware of use proprietry RF protocols. The Honeywell Hometronic system can be controlled through the Sensible Heat Web Interface or Web Manager but all of the control logic is within the Honeywell side of the system (you would be controlling setpoints and reading back room temperatures etc). It would also cost £2-£3k for a Hometronic system to be supplied & commissioned.

If you want to keep it low-cost then there really is no alternitive but to run some cables, that way you can use thermal actuators on the TRV valve bodies which can be controlled from relay outputs.

Regarding a heat pump, do bear in mind that a decent gas condensing boiler is still going to be more efficient with a radiator system. Heat pumps are most efficient at low flow temperatures and rarely can achieve higher flow temps than 55 degrees which is often not enough for radiators at there maximum heat demand (which is usually based with a flow temperature in excess of 70 degrees). This means you either need a supplementary heat source for winter use or have to replace your radiators with over-sized versions so that you get the additional heat you need.

Factor in the current gas & electricity prices and it would not normally make economic sense to replace a gas boiler (assuming it is a modern condensing version) with a heat pump. I say that as a mechanical engineer who works in energy management and also has a heat pump at home (I don't have mains gas available and have a new build with underfloor heating throughout which runs on a maximum flow temperature of 40 degrees).

[secureitall]

Neil
Thats great many thanks
RE heat pump
My Dad recently had a CO2 based sanyo unit installed that can achieve 65 degs without using the electric heaters. BUt i am waiting to see how it goes this winter. Plus his is a modern house (well insulated) and mine isnt.

I will hold fire on that plan. It is a modern condensing boiler but it runs on LPG so is dearer to run than a gas one.

RE the rads
I did assume the same. Any suggestions for wired TRV?
I will still need to read the room temp but i can run the cables req (Assuming low voltage) quite easily to the rads.

James

[neilball]

There are some new heat pump technologies that promote higher flow temps and as long as this does not effect the COP too much achieving the higher temps then it would be worth looking at. However electricity is still much more costly than other fuels so you need to be sure that the heat pump will reduce running costs as they rarely make for cost-effective retro-fit (either very long payback on investment or in some cases even higher running costs!). If you do have a poorly insulated house then you would be better adressing that first and then look at the boiler change at a later date.

For your radiator controls take a look at the Honeywell thermal actuators designed for underfloor heating manifolds as they also fit Honeywell TRVs. these are mains voltage as standard although I would guess they also do low voltage ones. Have a chat with a local plumbers merchant to see what they stock.

If you do fully zone the house then that could significantly reduce your current heating energy costs by upto 40% if you can right clever code to optimise the valve control rather than replicating basic thermostatic cycling. also make sure you demand-drive your boiler at the same time.

Finally if you do go down the heat pump route be aware that you may need to leave several radiators open all the time as a sort of bypass loop to keep the compressor happy, you certainly will not be able to close off all flow otherwise the heat pump will go into High Pressure alarm and most likely shut down.

[secureitall]

Brilliant.
I plan to properly run the valves (ie open/close in stages rather than fully open/close) with lpg if i can achieve 40% then i will be very happy.

I have got the touchscreen fitted in the hall ready for this and will be running the security on it over the next few weeks (speech announcment etc)

[neilball]

Just be aware that thermal actuators are just an on/off device you can only achieve modulated output by something called time-proportioning control ie changing the time spent with the valve powered and unpowered to allow bursts of heat into the room. This normally means some processing of actual temperature against required temperature to get a percentage heat demand and operating the valve accordingly, not trivial to get right! That said if you only use a couple of rooms at any one time then just switching off the others so you only heat rooms when you are using them will lead to some quite impressive savings.

[secureitall]

i see
i assumed they were motor controlled rather than solonoid so that some adjustmant was possible.
Im assuming then that you need to open the valve for lower percentages as the room approaches the desired temp, and vice versa.

[davee]

There is a radiator valve which takes the place of a standard thermo head, straightforward swap for a Drayton trv for example, and is controlled by rf from a wall mounted thermostat.
I cant remember the name offhand but if this sort of thing is what youre after I can dig out the details

[neilball]

Do you mean the Danfoss Z-wave TRV actuator? If so it is a bit of a cludge as all it does is switch between comfort temperature (set on the conventional TRV head using the standard 1-6 setting) and setback which is a fixed 3 degrees below the selected comfort setting. No temperature measurement or feedback, no demand to the boiler for efficient control etc.

[neilball]

Originally Posted by secureitall

i see
i assumed they were motor controlled rather than solonoid so that some adjustmant was possible.
Im assuming then that you need to open the valve for lower percentages as the room approaches the desired temp, and vice versa.

There are motor control versions that would fit - they are a larger actuator and more expensive than thermal actuators. Also worth noting that you can hear the motor operating in quiet environments which you will not get with the thermal versions.

If you arte doing true motor control then you need to think about resetting the actuator position at regular intervals and then adjusting the actual position based on room feedback. As I said to make it work well (rather than just thermostatic type control) is quite complex. The other alternitive is to buy in a system that you can interface to, this takes care of the HVAC strategy and lets you monitor temps and adjust setpoints through your integration gateway. While not cheap it will work "out of the box" and give you the highest levels of overall efficiency. Factor in a real payback of 3-5 years based on energy saved and it stacks up far better than most other high-value technologies you could fit instead. However it removes much of the fun/academic challenge of making it work yourself.

[JohnS]

I have Heatmiser networked stats connected to my groundfloor underfloor heating and use stat 8 which controls the upstairs rads which all have trv's. This controls the old boiler pump as oppossed to the underfloor pump.

They have various interfacing options, i use a web browser to setup the various programs for the room stats.

They also have an inline motor controled module for use with a rad in combination with a room stat which I haven't tried but certainly would if I was starting again.

While it all works well, the thing that I think is missing is some sort of ambient temperature interface, by that I mean an external temprature guage that could adjust the room stats up or down by a degree or two depending on how ward outside it is or which way the winds blowing (we live by the sea and when the wind blows off of the sea the house is definitly colder than when it comes off the land).

secureitall

What do you use to interface to your Galaxy?

[davee]

These people have some interesting products.

HouseHeat

including the remote control rad valves I was referring to

[KW1816]

Have a look at HouseHeat system - Automated Home Forums for some discussion on Househeat.

I considered it myself but decided I didn't really need full zonal control.

[davee]

You dont need to have full zonal control, start with one radiator at a time if you want at £69 a go. The big advantage is that the thermostat goes where you want to sense the temperature, not behind the curtains etc. and there is no mess or disruption to the heating system.
You can then be as adventurous as you want or funds permit after that.

[KW1816]

You dont need to have full zonal control, start with one radiator at a time if you want at £69 a go. The big advantage is that the thermostat goes where you want to sense the temperature, not behind the curtains etc. and there is no mess or disruption to the heating system.
You can then be as adventurous as you want or funds permit after that.

You could - but without control of most of your rads, or the boiler, all you can effectively do is reduce the temperature in each room, which you could do by turning down a normal TRV For me, I needed to be able to occasionally increase the temperature in a single room without affecting any of the others. To do this I’d need to be able to control all rads as well as the boiler ,for an individual room to be able to ‘call for heat’ while turning down/off all the other TRV’s.

The lack of simple integration to my Home automation server was another issue. In the end I installed Honeywell’s Smartfit – not a particularly clever system but it does allow me remote control of heating/water status and temperatures through my alarm panel. For the OP, this is using a dedicated hardware interface for the Comfort Alarm system called a UCM :: Welcome to Cytech Technology Pte Ltd ::.
My home automation server then talks to the alarm panel through the Homeseer plugin. I can then control the heating through Homeseer using a web interface, automatic event control or SMS - very handy and high WAF when returning from holiday