Monday, October 1, 2012

Cordless telephone chargers (Solar)

Three years ago (Feb 2009) I bought the following Panasonic cordless telephone system from Amazon consisting of 4 cordless telephones; a base unit and another three separate chargers. It works great and can't complain about it.  
Targeting to transform my house into a Zero-energy building, it was time to look at this small energy consumer and upgrade it to charge the telephones (not the base telephone since this needs power 24/7) using small solar panels.
I happened to have previously bought some submersible fountain pond water pumps from eBay for another project. I did use the small pumps but never had found any use for the 7.2v 1.12W panels, well until today! These panels match exactly the chargers for the separate cordless telephones. I plugged in a panel instead of the charger and it has worked OK for the past 45 days, i.e. the small solar panel was enough to keep the telephone batteries fully charged. Obviously, one panel per telephone is needed and the panel placement (in full sunshine) is of great importance to get maximum output from these small panels.

Below is a panel, 7.2v 1.12W
I have posted here details for building a simple battery based power supply for the base station.

Thursday, July 12, 2012

Solar Water Heater

Building of a Solar Water Heater.

This article is a description of a closed-loop Solar Water Heater (SWH) I have built and installed at my residence. Although today, the prices of SWHs have gone down in price, (also thanks to the government rebate), I must admit and others who bought a ready-made SWH will agree with me, that the quality of some brands has also gone down! Besides cheap workmanship with some Chinese brand SWHs, one thing I cannot stand is that most of the imported brands can't withstand Malta hot Summer or better have to be manually protected during the Summer months to reduce stress on the system. It's understandable that in Summer (or the warm months), the demand for hot water decreases and therefore only a small percentage of the daily heated water is used, thus hot water accumulating daily in the tank with an increasing temperature. This will pose more stress on the SWH storage tank and other components, resulting in a reduced lifetime! To overcome this problem, most of the installed SWH collector plates are covered in Summer to reduce heat absorption, heating less water and therefore reducing stresses. The SWH described here does not need to be covered, and all components are protected from this problem!

A good reference for starting to learn the basics on SWH can be found on the Home Power magazine web site. Please do visit the site since it will give you a good description of all the components I have used in this system.

System Description:
The system I opted for is a closed-loop, meaning that the sun will heat a liquid which in turn will heat the water though a heat exchanger. Although a closed-loop system is not a requirement for the country I live in since we don't have freezing temperatures and there is no need to empty the system at night, I still opted for this slightly more complicated system for the below reasons;
1) I wanted my home-made solar collecting panels and storage tank to last longer. This can be achieved by NOT passing water through the collector/storage tanks circuit but instead passing glycol. Glycol will not rust and prevents limescale from forming which has the side-effect of decreasing the system efficiency.
2) I did not want my SWH storage tank exposed to the elements, simple because I want it also to last longer. Using a closed-loop system, the storage tank can be easily placed away from the solar collectors
3) Decrease heat lose especially in Winter. In fact I placed the storage tank inside.
4) The SWH I've designed will have two three energy sources;
 - The sun, which will heat up the collector and the storage tank.
 - Log fire. I'll be utilising unused/escaping heat from the fireplace to heat up the SWH storage tank.
 - An electrical element which will be used when the above two sources are not enough

The pictures below detail the construction/function of the SWH.

The picture below is displaying one of the solar collectors without the tempered glass. The horizontal top (outlet) and bottom (inlet) pipes are 1/2 inch while there are ten 3/8 inch vertical laid copper pipes fixed to a matt black painted galvanised sheet. The total area of each collector is 2 m3.

The image below is showing the two solar collectors mounted facing South with a total collecting area of 4 m3. (The collectors in this picture are not yet connected). The supporting frame used is 3mm
galvanised steel.

The below image is displaying the underneath of the SWH tank. Connections:
1) Two connections inlet/outlet are used for the closed loop solar collector (heat exchanger circuit 1).
2) Two connections inlet/outlet are used for the closed loop fireplace source (heat exchanger circuit 2).
3) The middle large hole will house the electric 2KW element.
4) The other large hole will house the zinc anode.

The image below is showing the interior of the SWH storage tank. Notice the two circuits (left & right interlaced). The vertical copper pipes are about two-thirds the length of the storage tank.

The image below shows my neighbour Mario doing the copper brazing work on the tank circuits. He's a professional machinist by trade and therefore all this was a  piece if cake for him!

Sketch of all the SWH components connected...

The below image is the 'brain' of the system. Its all controlled by the Steca TR0301 controller. I won't be detailing here all the specifications of this controller however at a glance;
1) Can monitor 3 separate temperatures; Solar collector, SWH tank top and bottom water temperatures.
2) Pre-set with a starting differential temperature of 8°C
3) Cut-off differential temperature of 4°C
4) Cut-off maximum tank temperature of 60°C
5) Holiday function.

The below image is displaying the SWH components.
 - Top left is the 18 litre expansion tank. When the pressure inside the system increases due to high temperatures, the glycol moves temporarily into this tank to relief the pressure.
 - Below the expansion tank is an MCB box. An MCB is used to manually switch the electric heating element while the second MCB is used to power the differential controller.
 - Next to the MCB box is the Differential Controller.
 - Next to the Differential Controller is the internal circulation pump. This pump is switched on/off automatically by the controller and is used to circulate the glycol around the collector panels and heat exchangers inside the storage tank.
 - On top of the circulation pump is a small pressure gauge, measuring the pressure inside the closed-loop circuit.
- Below the pump are three values used to prime the closed loop circuit.

The below image is displaying the SWH storage tank pipe connections.
- The two top connections are the inlet/outlet to/from the solar collectors closed loop circuit.
- The next two connections are the inlet and outlet for the hot water system.
- The bottom connection is the 'hot' feed to the washing machine.

The below image is displaying the SWH storage tank with all the external components (on the left) and the inlet/outlet piping on the right.

The system has been in operation since 2008 without any problems. The sun does provide all of my family hot water requirements for a full eight months, while the remaining four winter months are assisted by the electric heating element.
Hopefully I will get all my hot water without using electricity including the winter months, since I'm currently working on the second circuit / heat exchanger to heat also the water using heat from the log fireplace. I'll be posting an article once this is ready and in operation.

Tuesday, May 22, 2012

Product Review - Touch Dimmer Switches

Touch Dimmers Review

This review is for a couple of dimmers I bought directly from TLC.

The Dimmers I'll be referring to are these;
 - 2 Gang 2 Way 400W IQMaster Remote Touch Dimmer Switch (VLIQ1402). Bought two of these.
 - 2 Gang 2 Way Slave Dimmer (VLIQS002). Bought two of these also.

Mains System Voltage: 240v
Mains Frequency: 50Hz
Load for the four individual dimmers;
  • 100W (incandescent bulb)
  • 100W (incandescent bulb)
  • 400W (rope light - incandescent bulbs)
  • 100W (5 x MR16 - 20W Halogen)
My intended configuration was to connect the master dimmers and the slave units to enable me to have a 2 way circuits, with the benefit of remote control!

For the benefit of the readers, I have copied below the technical data sheets as listed on the TLC website

iQ - Intelligent Remote/Touch Dimmer Switches
Employ the latest, state of the art, microcontroller based electronic circuitry and use current sensing to compute the load conditions. These products show progressive reaction to overload conditions, depending on the extent of overload as shown in the table below. iQ Intelligent Dimmer Switches are NOT suitable for use with Fluorescent Loads, including Energy Saving Lamps.
iQIntelligent Remote/Touch Dimmer Switches incorporate the following advanced features
Suitable for dimming Low Voltage Halogen lamps via good quality, fully dimmable electronic transformers.

Soft Start, which gradually increases the light output from the load over 1 to 3 seconds after switch on. The Soft
Start feature is also particularly beneficial when used to dim Mains Voltage Tungsten Halogen lamps which have inherent very high inrush current at switch on.

Overload reaction
Case Approximate load Power output to load when dimmer control is on the dimmer as set to maximum a percentage of its maximum rating
1 Up to 125 Load will receive maximum power continuously.
2 >125 to 150 Output to load will be reduced to 50% of the maximum after a delay of approximately 20 seconds after switch on.
3 >150 to 200 Output to load will be reduced to the minimum setting of the dimmer after a delay of approximately 20 seconds after switch on.
4 >200 Output will be disabled (load will be switched off) almost instantaneously after switch on.
iQ Dimmers:
Fused GLS Tungsten Filament lamps to BS161, rated at 230/240V. Dimmable wire wound or electronic Low Voltage Transformers of good quality.
Note: Transformer must be suitable for dimming using phase delay (leading edge) and NOT only phase cut (trailing edge) type of dimmers.
Warning: These dimmer switches are not suitable for use with Fluorescent Lamps or Energy Saving Lamps.

Well, looking at the above specs it's difficult not to be tempted to go for these dimmers! They are practically indestructible thanks to their overload functions, besides their soft start feature which will prolong bulb life.

I did install them however I'm very disappointed and I'm afraid I'll be looking to purchase something else, something better which works well, obviously!

Here is why I'm disappointed:
1) Dimmers get very warm when in use. This may be normal BUT all electronic components will have their working life greatly reduced when working close to their maximum temperature.
2) Dimmers are also warm when not in use. This should not be the case, since the load seems to be fully switched off. This can indicate that either a small amount of power is still being fed to the load or else the dimmer itself is consuming power when not used (the later is normal however it depends how much is the idle power!), both undesirable when my aim is to reduce power consumption.
3) Dimmers are almost all the time reacting to overload when in use. I'm suspecting this, simply because the lamps do not light more then 50%! This should not be the case! There is simply NO overload as can be seen from the loads which I described above which are all within the product specifications. On replacing the dimmer switches with normal switches, the lamps light up without problems. I even tested the circuit with a clamp meter to check for any wiring faults / short circuits and could find none! Once I reset the dimmers, they may work OK for some time and then we're back to an overload situation with just 50% of the available light.
4) Need to switch off the mains supply for the dimmers to reset. Although the specifications read that the switches will reset themselves automatically, they simply DO NOT. I have to turn off the main supply and restore back the power for the reset to work.

Something I did notice last Summer was that when I switched on the AC in the room where I have the dimmers installed, the overload situation disappeared, Yes problem solved! The room temperature was less than 20°C and it seems that this helps the dimmers in keeping them cool and therefore fully functional! To be honest, this is not acceptable because I can't keep the room cool for the dimmers to work!

Hope this review will help others in determining whether this product is a good for them or not!

Friday, January 20, 2012

Greywater System

Greywater System

This article will describe a multi-stage filtration system I built, to collect, clean and re-use water dumped from the washing machine. This water is eventually used as flushing water for a toilet.

The below flowchart lists the main steps I adopted to achieve my goal.

1. The washing machine performs a spin cycle during which water is dumped off.

2. Water from the washing machine is first collected into a buffer tank. The size of the selected tank is 100 litres. This capacity is more than enough to temporarily store a full washing cycle. This tanks serves two purposes;
  • Act as a buffer for the filtration/cleaning system. Since the adopted sand filters take time to filter the water and the machine dumps a large amount of water in a very short time  (during the spin cycle) water needs to be temporarily stored to be slowly processed afterwards.
  • The buffer tank is also trapping 'large' particles and stopping them from moving on to the next stage. This has been achieved by permanently fixing a piece of cloth just on the tank outlet.
3. From the buffer tank, water is passed through sand filters. The sand filters will clean and clear the water. I opted for three parallel filters to speed up the filtration process since the sand filters although doing a great job perform it very slowly!.

4. Water from the sand filters is passed through a 'fine grain' filter during which a small dose of bleach is added.

5. The water is dumped to a 500 litres storage tank. A toilet flushing is connected/fed from this tank.

One key feature of this system is that water flows between stages thanks to gravity! I have arranged the system in such a way as to eliminate the need for pumps which would have added cost to the system besides complexity and electricity consumption.


Since a picture is worth a thousand words, I have taken some pictures of my installation to better illustrate the system.

The below image is a photo of one of the sand filters laid on the floor. It's length is approximately 1 meter and is fully packed by fine grain sand. I've used 110mm drain pipes to construct the body of the filter, blocked at each end by screwable taps.

The photo below is showing an end connector of the sand filter. I drilled the 110 tap and installed a further 15mm adaptor which will be used to connect the filter to the rest of the system.

And this photo is showing the underneath of the TOP tap.

This is the photo of one of the BOTTOM taps. I have covered the outlet with a thick cloth (similar to what I did inside the buffer tank) to restrict sand getting out from the bottom of the filter. It turned yellow because of the glue which I used when it settled.

The 100 litre buffer tank, mounted on steel brakets using nine 8mm stainless raw bolts.

The buffer tank feeding the three parallel sand filters.

Displaying the three sand filters paralleled fed from the buffer tank and in turn feeding the 'fine' filter.

This below photo is the 'fine' filter which further cleans the water. I have placed bleach tablets inside this filter before feding the 500 litres storage tank.

The 500 litres storage tank.

The toilet flushing modification. Switching between greywater and the normal main water is just a matter of closing an angle valve and opening another, as shown below.

Note. Some parts of this system have been replaced as detailed here.