The human body has a specific heat of 3500 J/kg K/C scale and an average human is about 70 kilograms so ...
A ghost that can chill a human body by 1 degree (Centigrade please) has made a quarter million Joules disappear. Let's say the ghost manages to use half of that constructively: 125000 Joules.
A quick jog over to Atomic Rockets' Boom table shows that is the equivalent of about 30 grams of tnt or an anti-personnel mine. If it nails two crew it has the energy of one depleted uranium round from a GAU-8 autocannon. That's minimum because it is also picking up electrical energy and GHU knows what else (psionic points from your catatonic psi crew member perhaps.) That's not an entity you want running around loose on your ship.
Room temperature is 22 degrees, colder than the ghosty. It makes you feel cold by drawing on your heat. The cold spots paranormal investigators are fond of finding are no colder than their surrounding, merely pools of infra-dread (see my previous post). Ghosts are about 33 C and radiate a little heat allowing them to stand out from empty air on infrared sensors.
What do they do with the heat they steal? Where does it go? No one really knows. Any physical manifestations of NBEs seem to be low density gases that should be heated to high temperatures by the energy of a single human. Current theory holds that heat is either a drug or a catalyst required for their proper function. it also represents one weakness of NBEs.
Chill your surroundings and they're screwed they go dormant. A rookie psionic can herd them into a containment unit. Endothermic grenades work well for this. Ship's crews also use liquid hydrogen from their fuel tanks in a pinch.
Heat things up. Humans need oxygen but too much of it can cause toxic reactions in us. So it goes with haunts and heat. A rush of heat can hurt them. It better be a rush because the thing will use that heat energy in ways you will not like. Burning haunted dwellings and ships was an approved way of dealing with the haunters on Old Earth. Check out the tale of the Ivan Vassili. It's a seminal tale of a haunted ship with a hot resolution. These days some unreclaimable vessels are dropped into stars or nuked.
Laser weapons will work on NBEs. It's just hard to target a tiny spirit light reliably, especially through a light amplification sight.
NBEs are also known to draw power from electrical devices. This is the basis for our ftl and reactionless drives. In a controlled environment huge amounts of power are fed into NBEs that then use it to move our ships (preferably the way we desire. Electrical shielding will impeded them for a while, Faraday cages can trap them. Modern drives work on similar principles. A Faraday cage (at least the sort you rig up in a hurry or can transport) will not hold an NBE forever. It is a means to get the damned thing (perhaps literally) into a drive unit.
At higher tech levels electronic devices that can stun or hurt the NBEs are available. In general they are weapons of desperation to be used if the thing takes out your psionic. For one thing they are bulky (think many many battery packs hanging from you.) For another they can also do very bad things to a human's nervous system and nearby unshielded electronics.