At least one pressure exchange unit with a hollow cylindrical body, a piston sliding in the body, the piston including a piston head separating the interior of the cylindrical body into a downstream chamber and an upstream chamber, the downstream chamber being provided with a device for the admission and discharge of water to be treated, the upstream chamber being provided with a five-way distributor linkage including, for hydraulic balancing, two pressurized liquid supply orifices, two orifices for the evacuation of the liquid and an opening in communication with the upstream chamber.

A membrane process unit (MPU) is configured to receive a feed stream, subject the feed stream to membrane purification to generate a product stream and a concentrate stream, and subject the concentrate stream to energy recovery to provide at least a portion of energy for membrane purification. A concentrate recycle unit (CRU) is configured to receive the concentrate stream from the MPU, subject the concentrate stream to flow regulation to generate a waste stream and a recycled concentrate stream, and combine the recycled concentrate stream with a raw feed stream to generate the feed stream which is supplied to the MPU. At least one of a flow rate of the raw feed stream, a flow rate of the waste stream, or a flow rate of the recycled concentrate stream is varied, while each of a flow rate of the feed stream, a flow rate of the product stream, and a flow rate of the concentrate stream is maintained substantially fixed.

A reverse osmosis system includes a wheel formed of a hollow central hub, radial tubes fluidly connected to the central hub, semi-permeable membranes provided in each radial tube, a permeate outlet tube, and a concentrate outlet tube; a permeate collection tank; a concentrate collection tank; and a drive mechanism. The drive mechanism rotationally drives the wheel while the source liquid is supplied to the central hub of the wheel, the rotation causing the source liquid to enter the radial tubes in radially outward directions and cause pressure increase on the source liquid in the radial tubes. The pressure increase forces the source liquid through the semi-permeable membranes to separate into permeate and concentrate, the permeate being directed to the permeate collection tank through the permeate outlet tube and the concentrate being directed to the concentrate collection tank through the concentrate outlet tube.

An energy recovery device is provided in a seawater desalination system for desalinating seawater by removing salinity from the seawater. A pressure exchange chamber for pressurizing seawater by a pressure of concentrated seawater discharged from a reverse-osmosis membrane-separation apparatus includes a first supply and discharge port connected to a switching valve for performing supply and discharge of liquid, a second supply and discharge port connected to a directional control valve for performing supply and discharge of liquid, a flow resistor provided at the first supply and discharge port side in the chamber and configured to regulate the flow, and a flow resistor provided at the second supply and discharge port side in the chamber and configured to regulate the flow, and a flowmeter provided between the two flow resistors and configured to measure a flow rate of the liquid in the chamber.

A device for exchange of water molecule and temperature between two fluids. The device comprises thin molecular sieve membrane sheets that allow water molecules to permeate through while blocking cross-over of the exchanging fluids. The device provides two sets of flow channels having a hydraulic diameter ranged from 0.5 to 2.0 mm for respective process and sweep fluid flows. The two sets of the channels are separated by a membrane sheet having a thickness less than 200 m. The thin molecule sieve membrane may be prepared by forming an ultra-thin zeolite membrane layer on a porous metal-based support sheet which provides very high water permeance so that the exchange can be conducted in a compact membrane module at high throughput. The device can be used to remove water from a process stream of higher water content by use of a sweep fluid of lower water content or higher water affinity. For example, the device can be used to condition outdoor fresh air close to the temperature and humidity of indoor air by conducting humidity and heat exchange between the fresh air flow drawn from outdoors and waste air discharged indoors.

A heat-pipe membrane module belongs to a heat recycle device. The heat-pipe membrane module is composed of a membrane module and heat pipes. The whole heat pipe is placed in the membrane module where there is heat can be recycled; or one end of heat pipe is placed in the membrane module where there is heat can be recycled and the other end of heat pipe is outside the membrane module. Here, the heat pipe comprises a metal tube, wick and the working fluid, wherein, both ends of the metal tube have covers; the wick is evenly distributed in the inner surface of metal tube, which has a capillary effect; the working fluid fills the wick. The heat-pipe membrane module mentioned above is simple, cheap, and heat efficiency.

A heat-pipe membrane module belongs to a heat recycle device. The heat-pipe membrane module is composed of a membrane module and heat pipes. The whole heat pipe is placed in the membrane module where there is heat can be recycled; or one end of heat pipe is placed in the membrane module where there is heat can be recycled and the other end of heat pipe is outside the membrane module. Here, the heat pipe comprises a metal tube, wick and the working fluid, wherein, both ends of the metal tube have covers; the wick is evenly distributed in the inner surface of metal tube, which has a capillary effect; the working fluid fills the wick. The heat-pipe membrane module mentioned above is simple, cheap, and heat efficiency.

A system for reverse osmosis, RO, including a first RO stage (10) with a first feed inlet (11), a first brine outlet (12), and a first permeate outlet (13); a second RO stage (20) with a second feed inlet (21), a second brine outlet (22), and a second permeate outlet (23); and a pressure exchanger, PE, (40) connected between the second brine outlet (22) and the first feed inlet (11), wherein a first pressure difference ?p.sub.1 between the first brine outlet (12) and the second feed inlet (21) corresponds to a second pressure difference ?p.sub.2 between the second brine outlet (22) and the pressure exchanger (40). The invention further discloses a method for operating such a system for reverse osmosis (100).

Disclosed herein is a solar thermal osmosis desalination system comprising a forward osmosis subsystem and a reverse osmosis subsystem where the forward osmosis subsystem is configured to receive solar thermal heat and generate power that can be used to operate the reverse osmosis subsystem.

Disclosed are a hybrid system and method of waste heat utilization-based photovoltaic power generation and seawater desalination, wherein a photovoltaic power generation unit includes a linear Fresnel lens, a beam-splitting cooling tube, a solar cell, and a heat collecting tube; a seawater supply unit includes a seawater storage tank and a pre-treatment storage tank; a heat storage and temperature control unit includes a phase-change heat reservoir and heat exchangers; an electrodialysis unit includes poles, an ion-selective membrane, a desalination chamber, a concentration chamber, pole chambers, a concentrated liquid storage tank and a desalinated liquid storage tank; and an electricity storage and control unit includes a battery pack and a circuit controller. Incident sunlight achieves photovoltaic power generation by a light condensation followed by beam splitting mode; nanoparticle doped seawater absorbs long-wavelength light and transmits short-wavelength light.