Batch system
solar hot water heater converts to air conditioner. I live in a climate which experiences freezing temperatures but still for much of the year
hot water can be supplied by a roof mounted batch heater. Since these systems are drained into a storage tank at night there is no need for anti-freeze or any sort of electronic controls, thermostats, heat exchangers, circulating pumps or other expensive to buy and set up maintenance creating headaches. You simply fill the unit in the morning, shut off the
water once it's full and drain into your large storage tank in the late afternoon. No bells and whistles to break down. A float valve just like inside your toilet tank prevents overfilling. The system is not pressurized. Many breadbox style
heaters work this way.
Now the air-conditioner part. This only works in climates which
experience cool evenings after the heat of the day is over. I used to live where summer nights were so hot it felt like I was going to rot and this unit would not work in that sort of hellish environment. Since the batch heater is drained down in the late afternoon it is now available to cool water overnight. During the day this water would be stored in a large tank which is suspended from the ceiling just beneath the collector. A simple
pond pump would send water from this tank up to the collector at dusk each day and the water would be drained back into the tank early in the morning when the collector reaches its coldest point. Since the tank is up high , the air which it cools will flow towards the floor and no fan will be required. The tank will condense water on its surface and this water needs to be collected. A simple curtain would insulate the tank since it's cooling capacity is greatest in the early morning but will not be needed until the afternoon when the house warms up.
In areas where evening temperatures are not low
enough for this to work well you could still use a system similar to this if the temperature of your well water is sufficiently low. Each afternoon the air conditioning tank could be filled with cold well water. This water would absorb heat from the room and this warm water could be pumped into the batch heater in the morning. This preheated well water would now sit in the sun all day to provide your hot water. You get air conditioning and a more efficient batch heater
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