Project Name: HOUSE BARTLETT

Rainwater Harvesting and Supply System with Intelligent Controller

 

Location: Chintsa (Near East London) Eastern Cape, RSA

 

Customer Request Overview:

 

HYDRO DYNAMICS was approached by Mr. P. Bartlett who was in the planning stages for his retirement home to be located in Chintsa, Eastern Cape.  Mr. Bartlett indicated that he wanted to have a rainwater harvesting system that would be suitable to supply all water for his new home.  He further indicated that the system must be as automated as possible and require only minimal maintenance to run effectively and efficiently. The system should be “intelligent” in that it should be able to automatically switch itself between rainwater tanks and a municipal feed as the need occurred based on the amount of water available in the tanks at any given time.

 

After meeting with Mr. Bartlett and his architects regarding the project and discussing all aspects related to the rainwater system, HYDRO DYNAMICS was commissioned to design and supply the system.

 

 

System Design Overview:

 

HYDRO DYNAMICS began designing the House Bartlett rainwater harvesting and supply system from the roof down.  In other words, we started by looking at the amount of water that could potentially be harvested versus the space available for rainwater tanks and other system components in the proposed “tank area” of the Bartlett property.  We then looked at demand, how much water was required to supply the home comfortably on a monthly basis. After careful planning we were able to accommodate a total of ten, two thousand five hundred litre polyethylene rainwater tanks giving a 22 500 litre total storage capacity.  We supplied the high quality Nel Tank for this installation based on our previous experiences with their proven performance and longevity. The tanks are all interconnected at the bottom via a network of pipes and valves which make up a tank farm that will empty and fill simultaneously. Individual tanks can also be isolated should the need arise. For instance in a low rainfall period a lesser number of tanks could be used to raise levels and allow the system to be used instead of municipal water which is the client’s main goal.

 

 

Once the storage system was designed we then moved on to calculating the correct sized pump and pressure vessel for the home. Based on the client’s input we opted to go with a 1.65kW PENTAX CM210 Centrifugal Pump with the capacity to deliver up to fifty litres per minute in tandem with a 100 litre Hydrosphere vertical pressure vessel and pressure switch. These units combined will provide more than ample pressure to run the client’s home at the level of comfort which he expects.

 

 

 

The next step was to design an “intelligent” control system which would be capable of running the house automatically and insure that water from either the tanks or a municipal feed was available at all times.  This was accomplished by coupling an electronic control panel with a float switch inside the primary rainwater tank and two electronic solenoid valves.

 

 

 

 

 

 

 

 

 

 

 

 

The system is designed to work as follows:

 

A wall mounted electronic control panel is connected to a float level switch which is placed inside the primary rainwater tank. When the water level within the tanks drop below a pre-set level this switch sends a signal to the control panel which then takes the following actions on the two solenoid valves.

 

Solenoid valve number one, which is placed on the supply side just after the pump and is in the normally open position, will be closed by the control panel to prevent flow of municipal water back into the storage tanks. 

 

Solenoid valve number 2 which is placed inline on the municipal feed pipe and is in the normally closed position, will be opened by the control panel to allow municipal water to feed the house.

 

Once rainfall is received and the water level in the tanks rises above the pre-set level and the above scenario is reversed.

 

Other System Components:

 

The system also makes use of sieve bags specially designed by HYDRO DYNAMICS. These unique bags fit over the end of the rainwater inlet pipes leading from the roof and are used to filter out some of the sediment and debris that may wash down from the collection area from time to time.

 

Conclusion:

 

The complete rainwater harvesting and supply system is now installed in Mr. Bartlett’s home and functioning as planned.  Mr. Bartlett will give more feedback regarding the system once he has moved into the house in December and such feedback will be added to this study as it becomes available.