What do the scholars and experts of Islam say with regards to this case: can Zakat money be used to purchase a house that would be the orphanage?
Zakat cannot be used for the purchase of an orphanage, because an orphanage is an endowment. Giving Zakat makes the recipient the owner and the two cannot be combined
The only solution is what we have mentioned earlier, use a manoeuvre (Heela), a scheme. It is said in the construction of mosques and bridges and other public facilities the scheme is this: The Zakat is given to a poor person and he then is asked to spend it on these projects. The original donor of Zakat will be rewarded for this.
And Allah ﷻ knows best
Imam Ahmad Rida Khan رحمة الله تعالى عليه
Translation by Dr Musharraf Hussain Al-Azhari Translator of Majestic Quran, www.majesticquran.co.uk