Logistics and services
La logistique est l'art de bien ordonner les marches d'une armée, de bien combiner l'ordre des troupes dans les colonnes, les tems [temps] de leur départ, leur itinéraire, les moyens de communications nécessaires pour assurer leur arrivée à point nommé. (Baron Antoine-Henri, Jomini)
On this page, I will describe some of the logistical issues (transport, facilities, procurement, technical information etc.) and services (water, electricity) involved in reconstructing the old hut located on the Maiensäss at Luven used as a radio station in Switzerland.
- Hot water system Hot water obtained using just electricity is not an option on the farm. I built a system using 15 evacuated tubes (Figure 13), the hot gas inside these glass tubes heats a heat exchanger, that in turn, heats a water and food grade Propylene glycol mixture (3:1). This heated water mixture is then pumped through a heat exchanger located inside a 200 litre geyser. The pump runs off solar power. The process is managed by a control system that switches the pump on if the external heat exchanger reaches a temperature 6 degrees or more higher than the temperature of the water in the geyser. In turn the pump is switched off if the heat exchange process reduces this difference to 3 degrees Celsius. There is an expansion tank and one way flow valve in-circuit. The system has performed flawlessly since installation. I cover the evacuated tubes with a blanket when I do not need hot water. The radio shack will be equipped with a gas heat exchanger system as the shower installed in the shack will be used quite infrequently.
As a point of departure, there are no municipal services on the farm in South Africa where the radio shack is being constructed. This is a very good thing. This was the exact condition at the original Maiensäss hut located outside Luven during WW2 (and after). Farm huts located there had no services and conditions in the huts were very rudimentary. The operators had to make do with a diesel generator and water had to be carried to the radio shack, there was a nearby fountain. A pit latrine was used in the alpine hut, however, the reconstructed hut uses a flush toilet connected to its own septic tank.
In any event, the idea of some government instituted facility pretending it must provide me with water, and electrons flowing in copper wire, or even a sewerage system is plain crazy. Tomorrow they may want to prescribe how many times I have to breathe per day. Therefore the motto on this farm is; if you want to do anything, do it yourself.
The world and its peoples are far to reliant (and dependent) on manipulated and abused social "necessities" driven by government agendas. In this respect I am a bit like Henry David Thoreau, who said "All good things are wild, and free". This of course does not always apply to vintage radio equipment! I had the good fortune to visit the pretty little town of Concord, Massachusetts, located approximately 30 km west of Boston and visited the pond where Thoreau had built a small cabin to live in. Perhaps you have already, but in case not, if you get the chance read some of his works, and perhaps start with "Walden", it will do you good.
Water
- The site is in a high rainfall area, ~ 1000 mm average per year, although the last few years have been much drier and we are battling to fully recover from a drought we suffered during 2016. There are four possible sources of water, rainwater, a fountain ~350 m from the radio shack, a stream in the valley below the house and the Pholela river. Currently I use rain water collected from the roof of a metal shed (Figure 12), but am working on using the fountain as well. The fountain is at a higher elevation level so the water tanks could be gravity fed. This fountain tends to run dry towards the end of the winter. There is another fountain which runs stronger, several hundred metres away from and at a lower elevation from the radio shack. If I wanted to use this I would have to add a pump, so for the interim I will test the feasibility of using the fountain that allows gravity feed.
Electricity
- Currently, we have ~500 Watt maximum available directly from the Sun via 3 solar panels mounted on the rood of the main house. This will eventually be replaced by a much larger system consisting of sixteen 250 Watt panels (effective 180 watts each) mounted on the main house roof. The inverter will be a 5 kVA Victron (4 kW). I have designed and am building a combiner for all the solar panels, which will allow individual monitoring, fusing and isolation via switches of 4 groups of series/parallel arrays. This combiner also includes protection against voltage surges, lightning and excessive current withdrawal. A 48 Volt battery bank with a capacity of ~ 480 ampere hours will be installed. During sunshine hours enough power will be available for most requirements. Such a system of course requires that one be aware of the state of the batteries, what the weather is doing etc. so as not to abuse the batteries. The general rule I have been using is to not discharge batteries more than 10%. This increases their expected life time tremendously. For anything else, the diesel generator must be used. There are 2 independent armoured power cables between the radio shack and the main house. It is possible to switch between solar power or generator power for either the radio shack or the house. I will not be adding a solar power system to the radio shack, that will be an unnecessary and expensive duplication.
Transport issues
- The road or rather track, leading to the house and radio shack is not paved or tarred it is a soil track. This track can become very slippery if it rains. Before you reach this track, you normally have to use a secondary gravel road maintained by the government which becomes totally useless when it has rained, this gravel road turns off from the main tar road. There are several alternative ways to reach the farmhouse, these are all tracks through pine (mostly Pinus Patula (Southern Yellow Pine) ) and Eucalyptus plantations. I have been moving bits of equipment and furniture down to the farm, as we are moving out of the city (Pretoria). This is being done with a small truck and a trailer (Figure 15). I have to be very careful with the weather conditions (Figure 16), so always plan ahead to ensure the chances of clear weather is good when arriving so that I will not get stuck on the road. We have a small 4x4 vehicle on the farm, which is a bit better that the truck on wet roads. Heavy rains can also set the streams and Pholela river in motion (Figure 17) within a short period of time as the topography in the area is very hilly and slopes are steep, with the result that runoff runs fast.
Update April 2020
Since moving to the farm we have done a lot of work. We had to do much fencing for the horses, I built a stable and an arena. The soil is quite shallow at most places on the farm so many of the post holes I dug with a crowbar. Fortunately the layer of rock below the soil is a mud-shale, and can be broken up with some effort...
We installed four additional water tanks; we now have eight 5000 l tanks that are filled by roof water, or if need be topped up by a nearby stream. Water from these 8 tanks are pumped to two similar sized holding tanks which then gravity feed water to the house.
I have started work on a much larger solar system, which is still in progress. Stage one entails installing 16, 255 watt solar panels (maximum output is about 160 watt per panel). These will feed a combiner system that contains the fuses, switches, ground fault interrupt, surge arrestor and current meters for the solar panels.
Update June 2020
Finally, the 16 solar panels (4 sets of 4 each) have been installed. These face north-west at an angle of 43 degrees, i.e. optimized for winter. Power output in the summer will be approximately the as that obtained in winter.
The solar panel combiner box was constructed and installed (Figure 13). The battery bank consists of 8 Trojan SAGM205 absorbent glass mat (AGM) batteries, connected in a series/parallel configuration to create a 410 Ah, 48 volt system. This capacity is a bit less than what I originally had in mind, unfortunately the Rand/Dollar exchange rate has deteriorated once more, so I could not afford a larger battery bank. The batteries were charged individually before connecting them in two strings of four batteries each. This ensured the bank was balanced as far as possible at the outset.
Four additional panels were installed a week later and I plan to install an additional four facing north-east. This will give us a total of 24 panels, with a peak capacity of about 3.3 kW.
The good news now is that finally we can run the washing machine off solar power! Test have shown we can have up to 2.8 kW when the Sun is overhead and the sky is clear of mist, firebreak smoke and cloud. So, it does take a bit of power management, and one needs to be aware of what solar input power is available before using equipment that consumes much electricity.
The system can also manage a KWS-1 transmitter and 75A-4 receiver without any problems. When the last string of solar panels have been installed, one will have a reasonable amount of power even during misty or cloudy days. The system has an output of about 500 watts when overcast weather is experienced. It could be lower even, down to 200 watts if the clouds are very dark and non-transparent. These are exceptions however, and one learns quickly to adjust your consumption on days like that.
Update July 2020
During July I installed a small 50 liter geyser in-line prior to the main 150 liter geyser. The two are thus in series. When the sun is shining, and adequate excess power is available (normally from about 10:30 am) the small geyser can be powered directly from the solar power system. The effect of this combination is that the main geyser now draws hot water instead of winter cold water. This makes a huge difference in the final water temperature and hot water capacity. The main geyser is heated by the sun via a heat exchanger and evacuated tubes. In the summer the system copes well, but it suffers in the winter as the winter water which it draws can be close to freezing point! Whereas the system previously battled to get our hot water heated to 50 degrees Celsius, the main geyser now easily reaches 60 degrees Celsius. The whole family is of course very impressed with this new tandem geyser set-up, all powered by the sun.
I now have 24 solar panels installed. Sixteen face north-west, inclined at an angle of 43 degrees from horizontal. An additional four faces north-west at an angle of 15 degrees, and four others face north-east also at an angle of 15 degrees. One loses about 4% per year in efficiency due to the fact that the panels do not face true North. This combination is a very good compromise for power delivery throughout the year. Peak power has been measured at about 3.6 kW. This may improve as the sky is currently a bit hazy due to smoke created by the many firebreaks in the area being burned during this time of the year.
If you are interested to see how the solar panels are performing, click on the link below. It will take you to "VRM World" . This is a way to publicly share VRM site data through a searchable world map. Of course access to site configuration, precise location and any private details are excluded!