My automated energy monitoring requirements.

I've spent the last few weeks searching the internet for solutions to my automated monitoring requirements and, as is so often the case with the internet, have been overloaded with results. As with anything IT the pace of change is staggering and it's easy to get side tracked, especially by the emerging technologies So I've got to be quite clear and focussed in what I want.

This is what I think I need!

Temperature Sensors
Two wireless temperature sensors; one inside and one outside. I want them neatly packaged, battery powered and at least one will have to be weatherproof.

Meter Reader
A device which can read a conventional gas meter. This is quite a problem because it has to either read the digits or count the revolutions of the red pointer. Devices like this do exist but it has to be affordable

Data Logger
I need a central system to collect the data from the sensors. This could be my PC but that gets switched off and on. So practically, it has to be an independent system.

Firstly, of the many solutions available they categorise into commercial and private (not amateur because the knowledge level encountered never ceases to amaze me). Now the commercial solutions tend to be expensive whereas the private ones were ultra low cost but required packaging. As this energy saving work is a non commercial venture the private solutions are certainly the most attractive if the packaging problem can be overcome.

One of the most appealing solutions is offered by The Open Energy Monitor Project but I also like the approach of RFXCOM.

The Open Energy Monitor Project is based on an open, collaborative hardware and software development philosophy which has to be attractive but the building blocks may require me to have a little more equipment than I ideally require. But the prices look really affordable.

On the other hand RFXCOM has perhaps a more commercial rather than collaborative bias but have specialised in interfacing to mass produced products from other manufacturers. One example are Oregon temperature sensors which because they are mass produced are inexpensive and packaged for the consumer market.

Further considerations relate to the wireless standard to adopt of which there appear to be competing options. The other big decision is the choice of data logger. Should it be Arduino or Raspberry Pi based? Time to do more thinking and research.

Automating the meter reading process

My pre-occupation to date has been with monitoring and saving the energy used for heating. The reason for this is that I want a comfortable house to live in but at the same time relaxed in the knowledge that no energy is being wasted. As I've found it's not easy to identify where the heat energy is going. I'm leaving electricity monitoring until later because I consider this to be more straight forward and a lot about the self discipline of switching things off. And because it's winter it's much worse to be cold than, say, in darkness!

I've made considerable progress in demonstrating that a lot of valuable information can be extracted from some simple measurements. Information that can be used to make informed decisions to invest hard won earnings. However, the problem I'm now experiencing is that my manual observations are too labour intensive and contain inaccuracies. I now need to automate the process so that they reflect changes such as the boiler controller being manually overridden  or the room thermostat adjusted.  The graph of gas consumption vs degree days (difference between inside and outside temperature) illustrates this.

In a simple world heat loss is directly proportional to temperature difference and so the graph should be a straight line. In the real world wind makes a difference by creating ventilation losses and lowering the insulation value of the walls. And there's also heat gain from the sun etc.

It certainly looks possible to put a value on these effects and by so doing estimate the value of controlling ventilation losses or applying a wall treatment. (reference to earlier post). The trouble is much of the scatter in the graph is from the reading errors and hence the need for some automated help. I'm hoping that implementing an automated system wont be too difficult because there appear to be a number of expert communities on the internet developing some very promising systems. Here's hoping I can find something affordable and usable!

Why a house should work more like a car!

Alongside my energy saving work I've got problems with my car that's caused me to study in more detail how a modern car works. The problems I'm experiencing relate to the electronic management of the engine but it's occurred to me how the homes we live are years behind the technology used in most of the cars we drive every day and take for granted.

A modern car uses a wealth of sensors to gather data from many parts of the drive, chassis and engine components to make sure it is running safely and efficiently. For example, the engine management computer, in order to optimise efficiency, measures parameters such as the air flow entering the engine, the inlet manifold temperature and its pressure many times a second to control the fuel flow, turbo pressure and recycled exhaust gas . The electronics and components to achieve this are cheap and mass produced. So if this advanced energy saving technology can be applied to even the most standard of cars I'm sure similar systems would make a significant contribution to energy usage in homes.

What do smart meters offer the consumer?

I've just visited an elderly relative who has just had smart meters and the obligatory table top display installed. Now if you can detect a slight tinge of scepticism in my writing then you're right. So why do I feel like this?

Well I'm interested in smart meters because my energy and cost reduction work at home (documented at  www.conserveandsave.co.uk) requires me to take daily readings from the gas meter. It would be so much better if I could automate this and a smart meter would appear to be the answer. My expectation has been that these meters will have an interface that is open for use by the consumer but I'm confused and a little dismayed by my first research.

I may have misunderstood what I've read but the initiative seems to be focussed towards the energy supplier. With respect to the data from the meter it will be communicated to an independent company that will disseminate the data collected to authorised organisations. I couldn't find any information regarding an open interface from which I could directly obtain consumption data. (I hope the intention is not to have to apply to access it via the internet from this company!) However, the mechanism for local access must be there because it is being used by the table top display. It's not a revolutionary concept either. Since 2000 it was introduced in cars which through legislation must include a standardised open interface from which data such as engine temperature, speed, fuel used, fault codes etc. can be obtained to check correct operation and efficiency.

I hope my fears that this initiative is founded on bureaucracy and big business is ill founded!