More advantages of radiant heating

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Maintaining thermal comfort

Panel location can significantly affect the magnitude and distribution of room surface temperatures (MRT) and thereby affect required heater capacity necessary to achieve a given comfort level. When units are properly-sized and located, a higher MRT for the occupants is produced which then permits a lower air temperature for equal comfort conditions.

However, if the radiant heat is too concentrated such that the asymmetric temperature (difference between the plane radiant temperatures of the opposite sides of a small plane element is too much felt by the occupant then (local) discomfort occurs. Normally, discomfort should not be experienced by occupants in spaces heated by radiant systems if thermal comfort equations are satisfied and the asymmetric temperature is limited to 9°C .

Energy efficiency

Radiative transfer between the occupant and surrounding surfaces benefits from the difference in the fourth power of the temperatures as compared to the heat exchange by convection between the occupant and the adjacent air, which varies linearly with temperature difference. A study made by Kilkis (1992) showed that radiant heating can also increase the efficiency of a heat pump system. Zmeureanu et al. (1988) found out that the heat load and peak load of a radiant heating system was lower (77% and 80%, respectively) than conventional systems at the same level of thermal comfort. Since part of the sensible thermal load is handled by radiant ceiling panels, volume of supplied air can be reduced which in turn can reduce air transport energy (by 20%). This saving reflects a total energy consumption of 10% less than a conventional convective system. Further savings can be benefited with the use of radiant heaters by means of installing fast-acting surface
mounted-radiant panels. Watson et al. (1998) used a multi-sized ceiling-mounted radiant heater with higher watt density of 50 W/ft2 sized to the nearest 100 W of heated area and found significantly lower retrofit installed and maintenance costs compared to other types of heaters.

However, since radiant heating systems heat surfaces instead of the air in the room, higher surface temperatures (wall, floor, glass) occur and produce greater heat losses through the surfaces to the outside (transmission losses). This can be compensated by ensuring that the heated space is well-insulated.

Reduced air temperature gradient

Since radiant heating systems heat surfaces, there is very little air motion resulting in a more uniform room air temperature distribution. This can lead to a more uniform distribution of thermal comfort (in terms of PMV values) within the occupied zone and reduction of energy requirements.

Healthier air

Utilisation of thermal radiation to condition air reduces the dependency on air as the thermal transport mechanism while passing indoor air quality requirements. Thus, allergens (e.g. mold spores, dust, insects, pollens) and disease-causing microorganisms usually carried by the heated air medium can be reduced if not totally avoided. This advantage gives radiant heating systems an edge to wider range of applications, from residential and commercial buildings to buildings requiring higher indoor hygiene (e.g. hospitals, clinics, nursing homes, etc.).

Convenient operation

Complications attributed to circulating high volumes of air (e.g. more wiring, pipes, ducts and other installations) are avoided with radiant heating systems.

Efficiency of space use

The space consumed by a radiant heating system, be it hydronic or electrical, is
less than that of a variable-air-volume (VAV) system.

Zoning

Radiant heating panels can be installed in such a way as to provide zoning or conveniently placed in a location that needs radiant compensation (Simmonds, 1996).

REFERENCES

Dudkiewicz, E. and Jezowiecki, J. 2009. Measured radiant thermal fields in industrial spaces served by high intensity IR. Energy and Buildings 41 (2009): 27-35.

Kilkis, B.I. 1992. Enhancement of heat pump performance using radiant floor heating systems. AES 28: 119-127.

Simmonds, P. 1996. Practical applications of radiant heating & cooling to maintain comfort conditions. T ASHRAE 102 (1): 659-666 .

Watson, R.D., Chapman, K.S., and DeGreef, J.M. 1998. Case study: seven-system analysis of thermal comfort and energy use for a fast-acting radiant heating system. T ASHRAE 104 (1): 1106-1111 .

Zmeureanu, R., Fazio, P.P., and Haghighat, F. 1988. Thermal Performance of Radiant Heating Panels. T ASHRAE 94(2): 13-27.

Sisteme de incalzire prin panouri radiante - avantajele panourilor radiante

Panourile radiante creaza o egalizare a distributiei temperaturii pe inaltime, intre tavan si podea. Astfel, se evita formarea pernelor de aer supraincalzit care se localizeaza in zona tavanului atunci cand sunt utilizate alte sisteme de incalzire. Incalzirea camerelor cu tavane inalte cu ajutorul panourilor radiante da posibilitatea scaderii semnificative a consumului de energie.

Transmiterea caldurii se face fara pierdere de energie. Undele termice realizate electromagnetic transmit energia termica direct (imediat) si fara pierderi de transport catre toate corpurile solide din zona de radiatie. Temperatura optima a spatiului se obtine prin temperatura de suprafata a materialelor inconjuratoare si a obiectelor din incapere.

Incalzirea obisnuita cu apa calda, cu gaz sau cu curent electric, degaja caldura in principal prin convectie-suprafete. Suprafetele fierbinti degaja energie termica prin conducte termice in aerul din incapere - si doar intr-o mica masura prin radiatie termica. Cota parte de radiatie termica este totusi decisiva pentru clima care se simte in incapere. Astfel, din punct de vedere fizic, confortul sobelor de teracota este determinat de o cota mare de radiatie termica - unda de caldura comparabila cu cea apanourilor radiante. Sistemele de incalzire infratherm ce folosesc panouri radiante reprezinta o adevarata revolutie in acest domeniu, acest lucru datorandu-se multiplelor avantaje pe care le prezinta incalzirea cu aceste panouri radiante comparativ cu celelalte sisteme existente la ora actuala.

Principiul panourilor radiante

Principiul dupa care functioneaza aceste panouri radiante este identic cu cel dupa care soarele incalzeste Pamantul prin intermediul radiatiei infrarosii. Prin urmare, cedarea de caldura a elementelor de incalzit se realizeaza prin unda in infrarosu si convectie. Acesta produce radiatie termica cu un randament ridicat, fara electrosmog. Panourile radiante cu radiatie infrarosie la distanta este un sistem inovator de inalta calitate recunoscut pe plan mondial ca fiind liderul in materie de eficienta a incalzirii. Cele mai importante avantaje ale sistemelor de incalzire cu panouri radiante sunt: economia energetica si costurile de intretinere aproape inexistente. Exista posibilitati de incalzire partiala, de alegere a temperaturilor potrivit zonei, de programare a orelor de functionare.

Transmiterea caldurii fara pierdere de energie la panouri radiante
Undele termice trannsmit energia termica direct (imediat) si fara pierderi la transport catre toate corpurile solide din zona. Temperatura optima a spatiului se obtine prin temperatura de suprafata a materialelor inconjuratoare si a obiectelor de instalatii din incapere . "Vinovatul pentru pierderi", in cazul sistemelor termice obisnuite - conductele, tevile de apa, camera cazanelor, camine, convectoare, puturi de aerisire - dispar in adevaratul sens al cuvantului si astfel, se poate economisi de trei ori, si anume la:

· Costurile pentru energie
· Costurile de instalatii
· Costurile pentru reparatii si pentru revizii
Datorita faptului ca aceste panouri radiante sunt prevazute cu termostat, temperatura se mentine constanta in incapere, la valoarea setata, raspandindu-se uniform, in toate colturile incaperii.

Clima individuala si amenajare decorativa a spatiului cu panouri radiante
Instalatia panourilor radiante este foarte simpla si poate fi aleasa optim pentru orice spatiu individual. Se preteaza in aceeasi masura pentru spatii private, cladiri publice - de la aeroporturi, spitale, banci, hoteluri, cabinete medicale si pana la muzee, pentru birouri sau spatii de productie - de la sere si pana la spatii sterile fara praf. Amplasarea panourilor radiante se poate face pur si simplu dupa principii practice, rationale sau se pot interpune si accente individuale, creative de decoruri.

Avantajele panourilor radiante:

- Reducerea costurilor cu incalzirea cu pana la 30-50%
- Instalare rapida, simpla (pe perete sau pe tavan), cu costuri reduse
- Nu necesita aprobari, intocmire proiect, racordare la reteaua de gaze
- Nu exista pierderi de caldura ca la sistemele clasice (conducte, centrale)
- Incalzire rapida, fara consum de oxigen
- Mentine o umiditate a aerului constanta si optima
- Elimina mirosurile neplacute (fumul de tigara)
- Purifica aerul (ionizeaza)
- Ocupa mai putin spatiu fata de alte sisteme;
- Nu necesita o incapere speciala, aerisita, sau incaperi de depozitare combustibil
- Peretii se mentin uscati, nu apare igrasie, mucegai
- Sunt sigure in exploatare
- Nu necesita intretinere (revizii periodice, piese de schimb, etc.)
- Randament crescut comparativ cu alte sisteme de incalzire
- Nepoluante, nu exista deseuri toxice, noxe, CO2.

Plasmele termice sunt ideale pentru incalzirea eficienta a oricarui tip de spatiu:
- apartamente in blocuri, case sau vile
- case, vile sau case de vacanta
- pensiuni, hoteluri, moteluri
- cladiri de birouri
- policlinici, spitale, scoli, gradinite
- spatii comerciale
- restaurante.

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http://calduraieftin.ro/