What about those Whispergens ??

[Lindsay]

Ronald raises some very valid questions and it is timely that we address them as the experiences we had in Holland with the factory technicians visiting a great many WhisperGen installations highlighted some of the issues that were causing owner frustration unbeknown to us.
The noise problem on start up is a phenomenon common to high temperature burners. We have now identified the cause of this and have developed a new Evaporator that entirely eliminates this noise, at the same time boosting power levels, and reducing carbon build up. We hope to release these new evaporators when all testing has been completed. We have some units operating in the field on trial and the feedback so far has been encouraging.
The exhaust backpressure is a factor but not as critical as Ronald stresses. The main criteria is the need for condensation drains at low points and to provide the hull outlet with a weather shield to prevent wind and wave action causing a ‘surge’ of air to return down the exhaust. This is also common with any external combustion device. It is a simple matter of following the installation manual, the logic of which seemed to escape some ‘installers’ in the past.
The WhisperGen needs air to operate, as any heat engine does, internal or external combustion. It is not difficult to provide suitable ventilation; all the WG needs is a 50mm2 vent.
In answer to Ronald’s questions re the heating; the DC Marine WhisperGen was designed first and foremost as a battery charger/monitor. The heat produced during charge periods can be used to heat water for storage or for space heating. In other words; as an auxiliary heating device. Some of the early promotional material overstated this and many took it mean that you could run the machine 24/7 for heating. This misses the point and we are quick to point out that it is an expensive machine to use just as a heater. We have now developed a system whereby the WG has its own compact cooling system with a heat exchanger between this system and any heating circuit around the boat. This heating circuit can incorporate an inexpensive diesel fired water heater, excellent brands of which are available, to provide the heat levels that Ronald quite rightly demands; when the WG is running it supplements the main heater. We have installed several of these systems now and the results have been most satisfying to all concerned.
On the evaporator blocking issue we have also identified why that was happening and it turned out to be quite simple. The software controlling the WGs operation has a AI component that senses best exhaust oxygen content on start up. After the initial set up at installation the software program then monitors each start and adjusts the fuel/air ratio ever so slightly to obtain optimum clean burning. That’s great and it works really well, but, after considerable run time the evaporator, for whatever reason; bad fuel, etc, will start to get carbon build up. The software senses this and starts to increase the fuel flow on start up. This lifts the ‘Start Fuel’ value and will continue to do so on each subsequent start until the carbon build up is too great causing flame failure. This was usually happening, on good fuel, at around 1000 hours. So, the owner changes the evaporator and all is well-bit of smoke on start up but not too bad. Now the flame failure occurs at 500 hours. So another evaporator. Failure this time at 200 hours??? What’s going on?? It turns out that if the “Start Fuel” value is not reset to the default, clean start value, then the WG still thinks the evaporator is blocking up and will continue to start with a rich mixture which causes excessive carbon build up, which causes flame failure and so on; a classic ‘loop’ scenario. The software can only ‘up’ the fuel and not reduce it.
We have now issued instructions with all new evaporators to make sure this very simple reset task is carried out.
WhisperGens are still rolling out the door to very happy customers! (When installed correctly)