Green Building Forum - Cheap metering for oil boiler

Cheap metering for oil boiler

GaryB — Sun, 27 Oct 2013 08:32:19 +0000

My primary source of heating is an oil boiler and I really want to meter its consumption.

I can't use a Watchman or Apollo oil gauge to assist as the plastic tank has complex geometry - I can tell when it's full, exactly half full or empty but haven't a clue about in between.

At present I am assessing the consumption based on observed burner run times during start-up / 1st hour and for the maintained hours. This works reasonably well for the moment, as long as I don't adjust the set temperature or change the timer settings.

I have researched the oil meters on the market and am not prepared to pay around Â£250-Â£300 as this is the cost of my annual oil use. There are cheaper delivery flow meters on the market but these arenot accurate below 10 litres/min and my burner flow rate is 1.92 litres/hour.

I was thinking of measuring the burner hours run or the electical energy used. As the burner uses 103 Watts of electical energy to produce 19.2 kW of thermal and it is either 100% on or off, it's a straightforward calculation. For the latter option I have an Owl monitor which I can try, but I have found it to be pretty inaccurate at low energy use and it only seems to accept a single sensor, so electricity and oil could not be monitored.

Any ideas as to how this could be done for a budget of Â£50 to Â£60?

Cheap metering for oil boiler

SteamyTea — Sun, 27 Oct 2013 09:00:59 +0000

Can you wire in a plug in energy monitor to the oil pump circuit. Would need reading at the same time (every day or week).

The other way is to decant some oil into a smaller container and weigh it.

The CurrentCost meter can have up to 9 sensors, though to just measure the pump circuit you only need one. It does have some inaccuracies at all loads, but will give you a run time as it will be either 0 or higher.
The cheapest RPi is about 18 quid, transformer about a fiver and a CurrentCost about 50 (though there are thousands kicking about unused). I have some simple code to read it and instructions on what to do (not that I know what I am doing).

Cheap metering for oil boiler

GaryB — Sun, 27 Oct 2013 09:16:48 +0000

Posted By: SteamyTeaCan you wire in a plug in energy monitor to the oil pump circuit.

Tried that (used it to measure the Wattage) but it resets to zero each time the timeclock goes off.

The CurrentCost with multiple sensors could work, especially as I would be wanting to measure ASHP electrical consumption down the line.

Cheap metering for oil boiler

SteamyTea — Sun, 27 Oct 2013 09:22:49 +0000

Yes, it is annoying that they reset themselves.
I know I bang on about the CurrentCost meter, but it really is quite useful. They have an optical sensor that works with the DNO meter that is very accurate. Though I just calibrated mine to my actual usage and adjust for it. That only took a day with a plug in meter and found that it is 15% over.
Making a logger for it has been very useful.

Cheap metering for oil boiler

Triassic — Sun, 27 Oct 2013 09:48:14 +0000

Posted By: GaryBI have researched the oil meters on the market and am not prepared to pay around Â£250-Â£300 as this is the cost of my annual oil use.

I find myself wondering if it's worth the cost of monitoring at the daily usage scale, if you're only using Â£200 -Â£300 pa why not monitor at the annual scale, ie. Set an annual oil usage reduction target and see how you fare with that.

Cheap metering for oil boiler

Worcester — Sun, 27 Oct 2013 10:42:51 +0000

If you are OK with a soldering iron
Try this http://openenergymonitor.org/emon/
I currently have 15 environmental and energy monitors around my house, and the accuracy is spot on

Cheap metering for oil boiler

SteamyTea — Sun, 27 Oct 2013 10:48:29 +0000

How easy was it to get all the parts and what was the cost?
Thinking of going that route for Mk2 for my project.

Cheap metering for oil boiler

Ed Davies — Sun, 27 Oct 2013 10:49:17 +0000

Posted By: GaryB: â€œTried that (used it to measure the Wattage) but it resets to zero each time the timeclock goes off.â€

You can definitely get ones that don't - I have one. Uses two little hearing-aid type cells. Got it a few years ago. Actually, here's two:

http://www.amazon.co.uk/Power-Energy-Monitor-Esocket-Electricity/dp/B00E4H0M76/ref=sr_1_8?ie=UTF8&qid=1382870491&sr=8-8&keywords=plug-in+power+and+energy+monitor

â€œBuilt-in battery(3.6V rechargeable batteries ) backup - allows meter to be moved (and viewed) without losing readings.â€

Cheap metering for oil boiler

Ed Davies — Sun, 27 Oct 2013 10:54:46 +0000

Posted By: TriassicI find myself wondering if it's worth the cost of monitoring at the daily usage scale, if you're only using Â£200 -Â£300 pa why not monitor at the annual scale,

That's approaching a tonne of COâ‚‚ emissions so worth paying some attention to.

Also, measuring at higher temporal resolution allows better assessment of overall house performance - comparison against outside temperature, etc.

Cheap metering for oil boiler

Worcester — Sun, 27 Oct 2013 11:28:11 +0000

@SteamyTea
They sell all the parts on line, or you can use jeenodes, parts are pretty cheap, if you've got the time, then it makes a fascinating project. for example, I know right now that my 3 x inverter 14kWp PV system is generating 354W/404W/394W respectively, (it's raining cold and overcast!) the house is consuming a total 1152W of which 395W is being consumed/diverted by my Immersun. There is no way that the other units can be as accurate.

Here is the 'cheapest' oil meter that gets close to what GaryB was looking for, don't know if it is accurate enough http://amzn.to/1brU8mR it is just (obly just) outside his budget.. full details here: http://www.dunravensystems.com/portfolio/apollo-smart/ includes a USB link for uploading data as well.

Cheap metering for oil boiler

SteamyTea — Sun, 27 Oct 2013 14:17:15 +0000

Thanks Gordon
Shall look into that if I get the next lot of funding.

You have probably guessed by now that none of us like paying much for things

Cheap metering for oil boiler

CWatters — Sun, 27 Oct 2013 15:45:12 +0000

This meter claims down to 0.18L per hour but is expensive. Seems to need 6 bar so after pump only?

http://www.oilybits.com/braun-hz3-low-flow-heating-oil-meter-018--120-lph/prod_1068.html

Cheap metering for oil boiler

Sprocket — Sun, 27 Oct 2013 16:05:38 +0000

Those CT meters like Owl etc are generally set for full scale at something like 50 to 100 amps.
Your 0.4 amp boiler consumption sis less than 1% of full range so it is not surprising if numbers are not very reliable.

But it is fairly easy to adjust the sensitivity of a CT sensor. The sensor produces an (AC) electrical current. You just increase the value of the burden resistor so that the same current produces a larger voltage.

Cheap metering for oil boiler

CWatters — Sun, 27 Oct 2013 16:20:57 +0000

This sensor might be worth playing with as quite cheap. Claims 1% at 5L/hour. Pulse every 0.46mL. Only Â£22.

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=161067146449&fromMakeTrack=true&ssPageName=VIP:watchlink:top:en

This looks like same one. data suggests suggests it may work at lower flow rates if pressure is right?..

http://www.aliexpress.com/item/Diesel-oil-flow-meter-Gear-flowmeter-Flow-sensor-G1-2/707319034.html

Cheap metering for oil boiler

GaryB — Sun, 27 Oct 2013 17:16:18 +0000

Thanks everyone for the suggestions - I'll look into them all over the next few days.

I like the simplicity of the battery back-up plug-in meters suggested by Ed, I'll probably get one to start with.

In the longer term I'm interested in an all-in solution which can monitor electrical, water temperatures (DHW and heating flow) and PV output (a future aspiration). The most difficult to find it seems is the water temperature monitoring.

The most comprehensive system I have found is by MeasureMyEnergy, but it is rather pricey.