Have a play with this ....... moire pattern generator.

Andrew

This discussion is getting seriously out of hand (and off-topic?).

21 litres/day? AFAIK, the OP doesn't live in the Royal Albert Hall (nor even in "Albert's Royal Hall" as Albert Collins called it when he played there some years back)!!

Andrew

This also seems to be true of the new Philips CosmopolisWhite fittings installed here.

Andrew

Sorry, but that simply is NOT true. The efficacy of production LED lamps for street lighting is about 75 lumens/watt. Low pressure sodium lamps are still the most efficient at over 140 lumens/watt.

Andrew

Water extraction falls with room temperature. If the room is unheated, the extraction rate is much lower than the headline rate in the advertising. We had an Ebac 2000 series & used it in an unheated drying room (apart from the gas boiler that heats the house) - it took a couple of days to fill the tank.

I think that the COP (Coefficient of performance) for a dehumidifier is between 1.5 and 2 - maybe half that of an air source heat pump, so yes it will give out more heat than the electrical energy it consumes. For this application, the best way to use it would be to put it in the smallest room, keep all the doors and windows closed, leave it on permanently and adjust the humidistat to keep the RH below 60%. In that way, you can ensure that the RH never strays above 60% and minimise electricity usage.

If the humidistat is correctly set, and the RH is naturally below 60%, it will not switch on, so there is no need to switch it off manually or use a timer.

Andrew

Sorry, Algi, but your arguement makes no sense.

If the humidifier never switches off then either the humidistat is set at too low a RH level or alternatively the humidifier isn't man enough for the job. Using a timer only reduces running costs in the same sense as switching it off does. Practically, it is of no help in keeping RH at the desired level.

Andrew

True - but local authorities are in a bit of a financial hole and that drives many of the seemingly daft decisions. What worries me most about this kind of PFI "scam" is that council tax payers will be paying for the new lighting systems for the next 25 years (or more).

The efficacy of LED lamps is rising exponentially and will better all other light sources within the next few years. According to current forecasts (see: http://en.wikipedia.org/wiki/Haitz%27s_law ), production LED lamps will exceed 200 lumens/watt by the year 2020 (under laboratory conditions, that has already been achieved). No doubt it'll only be a year or two before someone will be able to justify spending many more hundreds of millions on replacing the current generation of "new" lighting installations.


Andrew

A brief follow-up. I managed to locate a copy of the Oldham Borough business case for the street lighting replacement.

I haven't read it all yet, but it does say that residential areas in Oldham will be lit by "Cosmopolis White". This a modern Philips discharge lamp with an efficiency of "up to" 117 lumens/watt. Apparently, they can be dimmed and do last much longer than the old SOX lamps. There are two types of these "Cosmopolis White" - one with a colour temp of 2800 degK (which I guess is what we have here) and one with a colour temp of 4000 degK. The old fittings were low pressure sodium with an efficiency of over 140 lumens/watt.

Mmm ........

Andrew

Sorry folks, but you are going to have to IGNORE the above photos and my comments about using a tungsten WB setting for LED lamps.

Why? Have a look at this ..........




I took that a few minutes ago. It's the first time I have really looked closely at the new fittings themselves. Those sure don't look like LED lamps to me.

When I first saw them lit, I thought they looked just like the colour of a high pressure sodium lamp - and there's a very good reason for that. They ARE high pressure sodium lamps.

I feel a scandal coming on .........

Andrew

A dehumidifier costs about the same as a fridge to run - 'coz that's basically what it is. It should have a built-in humidistat that switches it off once the Relative Humidity (RH) has fallen to the humidistat set-point. If you want to keep the running costs down, put it in the smallest room you have and keep the room as reasonably sealed as you can. Using a timer might not have any effect on running costs, as the dehumidifier will still need to extract the same amount of water to keep RH at the same level.

Heating a room will reduce RH but increases the capacity of the air to hold water vapour. This can result in an increase in condensation if you use a fan heater intermittently. An open fire should help, because it massively increases the air change rate in a room, so takes all the warm damp air up the chimney.


Andrew