I did not understand the question. you heat water that finds it in a greenhouse by using the solar energy. if the water flows in a closed pump-Changer" then you can change your heat carrier. If the water finds in the open air 'basin' then it is easiest to increase the temperature of the water.

yes good idea

Thanks, dear @ Abderrahmane Kechekhouche, 

Yes, water flows a closed pump-changer, but why can increase temperature if solar radiation is not controlled. I want really to increase temperature of water heated by solar energy ..

Dear Ali,

it is very easy to increase the temperature + 120 C by solar energy but you must choose the right system and do not grow the system otherwise you will have the superheated vapor and its may spoil the pump.

Dear Abderrahmane, water is heated by solar panel in winter, temperature is low .. that because I search ti increase temperature with actual set-up

There are several ways of increasing the temperature of the water-temperature or high temperature by using the solar energy. Expensive systems and other not.

it is a circle

Pump -------- solar concentrator +120C -------------- the greenhouse

pump ----------------------------------------------------------------- heat exchanger

I want to use nanofluid, how why its used in this systems? 

Nanofluid to Expensive. You can have good results without nanofluid.  I am a simple man and I love the simplicity. Maybe another researcher can answer you. 

Thanks, dear Abderrahmane

You are welcom Mr. Ali. Don't forget my journal. A small article from you is always welcome

https://www.ijeca.info/index.php/IJECA/index

I will never forget your journal Mr. Abderrahmane. I wish we will have other subjects of collaboration.

Dear Ali,

You can increase the temperature of greenhouse by using a solar concentrating system and make more isolation of your greenhouse.

with best regard

Ahmed.