” MERC-USAID project M20-076 “Solar powered Desalination and pumping unit for brackish water”
Two small scale desalination units (ROWPU & DELTA-15) were installed in Jordan under a subcontract signed between the Midwest Research Institute acting through its National Renewable Energy Laboratory (NREL) Division, Colorado-USA and the National Energy Research Center (NERC), Amman, Jordan. Also, this subcontract was signed under a prime contract was signed between the Midwest Research Institute and the U.S. Department of Energy (DOE).
The first desalination unit, ROWPU, was installed in the village of Qatar located 40 km north of Aqaba city, in order to supply about 500 inhabitants with potable water. This unit was driven by a diesel generator.
The second unit, DELTA-15, was installed at the campus of the Aqaba International Industrial Estate (AIIE) to supply customers within the estate with potable water. This unit was driven by a hybrid utility/photovoltaic generator (see Figure 5A). A plot of 2000 m2 was allocated for the infrastructure and installation of the RO facility.
The pilot desalination plant consists of the following units:
- A raw water well that was drilled in the framework of the project
- A concrete building (75 m2) for housing the PVRO system
- The RO desalination unit including sediment pre-filter, high-pressure pump, reverse osmosis pressure vessels, membranes, automatic permeate flush system and control system
- The PV-power supply system (e.g., inverters, charge controllers, storage battery bank)
- A raw water storage tank (35 m3) made of glass fiber reinforced plastic (GRP)
- A product water storage tank (5 m3) made of galvanized steel. This tank is no more used, because fresh water is pumped directly to the main storage reservoir (2900 m3) of the AII
- Two parallel concrete foundations (27m x 2m x 0.5m) to mount the PV arrays
- A brine evaporation pond (600 m2) coated with a special liner to prevent soil infiltration of brine (see Figure 5C)
- A boundary fence made of galvanized steel mesh
- A steel gate for the project's site.
The PV power supply system consists of the following main components:
- A PV generator with a total peak power of 16.8 kWp. It consists of 140 silicon mono-crystalline PV panels each rated at 120 Wp (Kyocera KC-120-1)
- A battery bank with a total storage capacity of 73.44 kWh. The battery bank consists of 24 sealed lead acid batteries each rated at 12V / 255Ah (Concorde PVX-2580L)
- Four pure sine-wave inverters/chargers, each rated at 220V, 50 Hz & 3.3 kVA (Xantrex SW3048E)
- DC disconnect boxes (PSDC1 & PSDC2), shown in Figure (4), manufactured by Outback / USA. Both boxes hold the required DC circuitry such as DC bus-bars, DC circuit breakers and DC connectors, which are required to connect the battery bank, PV sub-arrays, PVCCs & Inverters (see Figure 5B)
- AC disconnect boxes (PSAC1 & PSAC2) manufactured by Outback / USA. Both boxes hold the required AC circuitry such AC bus-bars , AC circuit breakers and AC connectors, which are required to connect the AC output lines of the inverters and utility grid connection lines
- A battery bank consisting of 6 parallel strings with 4 series batteries in each string to obtain the required system DC voltage (48 V). The battery bank is placed inside the power conditioning room within a special rack
- Six PV Charge Controllers (PVCC) installed inside the power conditioning room. Each PVCC charges the battery bank from a PV sub-array.
- Three-phase backup utility grid power obtained by AC IN circuit breaker.
- Three-phase output power obtained by AC OUT circuit breaker.
Operational characteristics of the DELTA-15 desalination unit:
- Fresh Water Production: 50 m3/day (18250 m3/year)
- Total Required Electricity: 180 kWh/day (65.7 MWh/year)
- Total PV Produced Electricity: 84 kWh/day (30 MWh/year)
- Total Required Grid Electricity: 96 kWh/day (25 MWh/year)
- Solar Fraction: 47 %
- Energy Consumption: 3.6 kWh/m3
Figure 5. DELTA-15 desalination unit; (A) PVRO pilot plant concept; (B) DC disconnect boxes;
(C) Brine evaporation pond; (D) RO desalination unit