Sensible vs Latent heat
Could someone help me explain what the differences is between these two concepts? I've been to a dozen websites that go into Einstein-speak... that's not what I need.
1) Natural gas furnace, blowing warm air: Is that Latent or Sensible?
2) Heat pump blowing ambient air: Latent or Sensible?
3) Fireplace burning an oak log: L or S?
Huge help, thanks.
senible is temp that can be measured. Example a thermometer. Latent heat is heat added but cause a change in state not temp. Like 212 water to 212 steam. the heat added to change water to steam is latent.
latent and sensible
sensible heat = If a subsatance is heated and the temperature rises as the heat is aded the increase is called sensible heat. Like wise if heat is removed from a substance. If the temperature falls the heat removel is also called sensible heat Heat which causes a change in temperature in a substance is called sensible heat
latent heat= It has been established that all pure substances are able to change there state. solids become liquids and liquids become gases. It takes the addition of heat or the removal of heat to produce these changes. Heat which brings about a change in state with no change in temperature is called latent heat.
All of your examples, OP, are sensible heat.
sensible =change in temp......makes sense latent=hidden head, change in state, change in Rh. cannot be measured as easily
Sensible Heat vs Latent Heat
Hi DCN 289.
To answer your question, all of the examples you listed are sensible heat.
Sensible heat can be measured or felt when increased or decreased.
Latent heat is heat gained or removed which causes a change in state of the substance, but not a change in measurable temperature- for example as ice melts into water or refrigerant converted into a gas or liguid. It is refered to as "hidden heat".
In the field of AC for example, Latent heat would be the heat gained as refrigerant boils in an evaperator from a liguid into a gas, but without a change in measurable temperature. If heat was continued to be added until it completely boils all the refrigerant into a gas it would now superheat the refrigerant which then is measurable and thus becomes a sesible heat.
I hope this was helpful.
In air conditioning most heat loads contain both sensible and latent heat. As sensible heat is removed from the air, the supply air temp drops. As latent heat (humidity) is removed the temperature remains constant as the moisture in the air is removed and goes down the condensate drain. Humidity is often referred to as the latent heat load.
I want to thank everyone who took the time to reply... enormous help to me.
I think I hit a stumbling block when I started to research it myself, so I turned to the HVAC-talk. It is evident that you all (as an industry) really think about what is physically happening to the air... My 10 year old asked me "dad, if we "turn up the heat" to make it warm in winter, why don't we "turn-down the cool" to make it cooler in summer?" She wanted to know why warm-air generation is called "heat" but cooling it is referred to only as "air conditioning" ... To me, both instances are "air conditioning".
One last comment. Trainiac brought up a good fact that sensible heat will co-exist with latent heat. My last sentence of my first response was not clear on that point. My example of refrigerant being boiled off will have sensible heat that can be measured, but that sensible heat should thoretically remain constant until all the refrigerant is boiled off and then any additional heat added will increase the sensible heat.
Originally Posted by DCN289
To answer your daughters question- in theory, there is no such thing as cold, but either the absence of heat or presence of heat. We could say we increase the heat in winter and reduce the heat in summer to be technically correct for the scientist sake.
Lastly, from a technical standpoint, air conditioning not only includes a comfortable temperature and humidity, but also conditions the air quality from pollution, particles, mold, spores, dust and stagnant air to name a few.
Hope this helped too.
I've only just recently started in the HVAC business... I've been studying various texts and understand Sensible vs Latent... but it didn't really occur to me that dehumidification (as well as humidification) would be latent heat. Thanks for pointing this out!
Originally Posted by trainiac
HVAC 101 Test
It's Not Rocket Science, But It is SCIENCE
with "Some Art". ___ ___ K EEP I T S IMPLE & S INCERE
Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities
. My 10 year old asked me "dad, if we "turn up the heat" to make it warm in winter, why don't we "turn-down the cool" to make it cooler in summer?" She wanted to know why warm-air generation is called "heat" but cooling it is referred to only as "air conditioning" ... To me, both instances are "air conditioning".
We don't turn down the cooling when we want it cooler, just because people got use to up being more.
You are correct. Air Conditioning is: heating, cooling, humidifing, dehumidifing, or cleaning/filtering AIR.
it's mean you didnt understand what is latent and sensible heat..
Originally Posted by platchford
learn it again..