Gas for heating and cooling

Gas for heating and cooling

We are not connected to the electricity grid and that makes the simple tasks like boiling the water for coffee different to most households.  We use LP Gas as the main source of energy to drive the equipment that is very energy hungry.

Although we have a solar panel and battery pack to supply us with electricity, these energy hungry activities are best managed with gas.  They simply use too much electricity to be supplied by our solar system.
 

Stove

The stove is used quite often in our house and the interesting fact is that it is mostly used to boil water for our hot drinks like tea and coffee.  On average we boil 750ml of water every 2 hours or so during normal activity in the house.  That leads to a total number of kettles to heat at between 6 and 8 per day.  If it takes 5 minutes to boil the water it means that one large burner is active for 40 minutes per day.

The other thing about heating the kettle is that you mostly want the water hot as quickly as possible.  Therefore we use the larger burner to heat the water.  The amount of energy that is lost by setting the flame too big is substantial, but I understand that the timing is an issue.

The dinner preparation takes about 1 hour every evening and then at least 1.5 burners will be active during that time.  So dinner uses a substantial amount of gas, but it equates to almost twice the amount of gas used to heat the water for drinks.

Oven

My wife bakes excellent homemade rusks.  These rusks are kept in the oven for an hour to bake and two hours to dry afterwards.  The oven's lowest temperature is 180 degrees C and that is achieved by burning two long burners at the bottom of the oven, for baking and the drying. 

The gas used by these burners is approximately the same as one of the large plate burners and uses quite a substantial amount of gas.  I am not happy with the heat distribution within the oven.  I will build another oven for my wife to do more baking, where the heat can be better regulated and distributed in the oven.

Fridge

Our fridge is a combination fridge and freezer on top.  It has the option to either use LP gas or electricity.    There is a small flame burning at the bottom of the exhaust pipe at the back.  That heat is used to make the heat transfer gasses flow through the pipes to cool the compartments down.

It was easy to determine the energy use when it was connected to the batteries. The electricity is used to heat an element that performs the same function as the flame.  That is not very energy efficient, but it allows for redundancy in the system in case we run out of gas.  As an emergency workaround it works well, but will not work on a more permanent basis.

A small thing to get used is that there are no electrical light in the fridge. 

Shower

We have a shower in the guest bathroom and the bath in the main bedroom's bathroom.  The shower is on a separate gas line to ensure the isolation of heated water and a separate gas supply.  

When the gas was finished in the three 19Kg cylinders feeding the stove and fridge, we simply moved the cylinder that feeds the shower, to the case that holds the rest of the gas bottles.  That allowed us time to refill all the other cylinders.

We have the shower's gas as a type of emergency reserve for the rest of the appliances.  

We use approximately one 19 Kg cylinder of gas per month for the shower and two 19 Kg cylinders for the stove and fridge.  That is for our family of 3 people.
 

The Future

Although we are happy with gas as the main energy source for the heating and cooling, the costs are still linked to the oil price.  It proves to be not an efficient solution for the long term.

We have investigated bio-gas and will start with the production of the bio-gas as soon as we have our animals in their sleeping quarters.  Their manure can then be used to feed the bio-digester that would produce the needed bio-gas.

More details can be found on  www.biogaspro.com

The ideal situation is to use the bio-gas in an additional burner plate in the kitchen.  Although the heat properties of the methane gas are lower than LP gas, you can use a larger quantity to get the same result.  

As most of the cooking is done during the day, the digester is mostly active in the day.  That means that the storage of gas can be smaller if the gas is used as it is generated.  In the case where the oven needs to be used, the LP gas option is still available.  

So eventually the bio-gas can be used as the primary source of heat, with the backup of the LP gas to cater for the situations where the bio-gas is not available or suitable.

We are using LP gas as the current source of heating and cooling and it is workable, but there is enough incentive to look further and develop a more sustainable and cheaper source of gas.

Till next time