منظم الحرارة قرب النافذة.

Because Arabic normally omits is/are in the present tense.

So منظم الحرارة قرب النافذة is a complete sentence even though there is no separate verb. It literally looks like:

• منظم الحرارة = the thermostat
• قرب النافذة = near the window

In natural English, we supply is: The thermostat is near the window.

This kind of sentence is called a nominal sentence in Arabic.

Yes. منظم الحرارة is an iḍāfa construction, often called a possessive or noun-link construction.

It is literally:

• منظم = regulator/organizer
• الحرارة = the heat

Together: regulator of the heat, which in context means thermostat.

In an iḍāfa:

• the first noun usually does not take الـ
• the second noun can be definite, and that makes the whole phrase definite

So منظم الحرارة means the thermostat, even though منظم itself does not have الـ.

Because it is the first part of an iḍāfa.

The first noun in an iḍāfa:

• does not take الـ
• does not take tanwīn

So you get:

• منظم الحرارة = the thermostat

not:

• المنظم الحرارة
• منظمٌ الحرارة

Those would be wrong in standard Arabic for this structure.

It behaves like near, but grammatically it is often treated as a noun of place / adverbial expression rather than a simple preposition.

In this sentence, قرب النافذة means near the window.

A useful way to understand it is:

• قرب = nearness / near
• النافذة = the window

So literally it is something like in the nearness of the window, but in normal English we simply say near the window.

Learners often compare it with قريب من:

• قرب النافذة
• قريب من النافذة

Both can mean near the window, though the structure is different.

Because قرب is linked to النافذة in a construction similar to iḍāfa.

In fully vowelled Arabic, this part would usually be:

• قُرْبَ النَّافِذَةِ

Here:

• قربَ is in the accusative as an adverbial expression
• النافذةِ is in the genitive because it is attached to قرب

So even though short vowels are normally not written, the grammar behind the phrase is still there.

A fully vowelled version would typically be:

مُنَظِّمُ الحَرَارَةِ قُرْبَ النَّافِذَةِ

This shows the grammar clearly:

• مُنَظِّمُ — nominative, because it is the subject/topic
• الحَرَارَةِ — genitive, because it is the second noun in the iḍāfa
• قُرْبَ — accusative, because it functions as an adverbial expression
• النَّافِذَةِ — genitive, because it is linked to قرب

In normal everyday writing, these case endings are usually omitted.

Without full case endings, a learner-friendly pronunciation is:

munaẓẓim al-ḥarārah qurb an-nāfiḏah

If you want a more careful grammatical reading with endings, it is closer to:

munaẓẓimu l-ḥarārati qurba n-nāfiḏati

A few pronunciation notes:

• ظ in منظم is an emphatic z sound
• الـ in الحرارة is pronounced clearly: al-ḥ...
• الـ in النافذة assimilates because ن is a sun letter, so it sounds like an-nāfiḏah, not al-nāfiḏah

No. Another very common way is:

قريب من النافذة

That also means near the window.

The difference is structural:

• قرب النافذة uses قرب as an adverbial/noun-like expression
• قريب من النافذة uses قريب as an adjective-like word plus من

Both are common and correct. The sentence you were given is a neat, compact MSA style.

Yes, but the original order is the most straightforward.

Normal order:

منظم الحرارة قرب النافذة
= The thermostat is near the window.

You can also front the location for emphasis:

قرب النافذة منظم الحرارة

This is still understandable, but it gives more prominence to near the window.

For learners, the original order is the best one to remember first: thing + location

It is a complete sentence in Arabic.

That is because it has:

• a subject/topic: منظم الحرارة
• a predicate: قرب النافذة

Arabic does not need a present-tense is to make this complete. So although it may look short, it is a full sentence, not just a fragment.

Yes, it could be indefinite, but that would change the meaning.

Your sentence has:

• النافذة = the window

So it means near the window.

If you said:

• قرب نافذةٍ

that would mean near a window.

So the definite article الـ on النافذة tells us the window is specific or already known from context.