ZEMCH 2019 International Conference Proceedings April.2020 | Page 291

that  at  the  bottom  by  0.2  to  2°C.  The  40W  pump  gives  a  water  flow  rate  of  between  0.86L/min  and 
1.5L/min through the floor‐HR and the U‐tube. With the pump running continuously, the surface of 
the floor can be kept at 15°C only when the outdoor temperature is not colder than 10°C. This surface 
is the top of 45mm concrete above the 100mm thick metallic‐clad insulation on ground. This ground 
level is also the top surface of the concrete floor of the adjacent garage. The temperature at the center 
of this 4.88m x 6m garage concrete floor surface was measured at 12°C.   
  There  is  therefore  a  3°C  difference  between  the  surface  of  the  HR  floor  and  ground  surface. 
Simulations  with  EnergyPlus  Slab  preprocessor  shows  that  This  temperature  difference  across  the 
insulated floor can be reduced. Simulations show that tf the indoor temperature is maintained at the 
average of the NatHERS heating thermostats of 18.75°C, after 6 years, the ground temperature would 
be 18.12°C i.e. a difference of only 0.63°C, if the perimeter of the floor is surrounded by 600mm deep 
insulation.   
5. Discussion 
5.1. HR‐floor.   
In accordance with the National Construction Code, 300mm deep insulation with R‐value of not 
less than 1 m2.K/W will be inserted at the perimeter of the HR‐floor. Simulations by EnergyPlus’s 3‐D 
slab preprocessor shows with the indoors kept at the time‐weighted average of the heating thermostats 
of 20°C daytime and 15°C nighttime it will take 5‐6 years for the temperature below the floor to stabilize. 
6. Conclusions 
After the HR‐floor is insulated vertically, data will be taken over the next 5‐6 years, to see if the 
15.5±1°C water heated by the 50m‐deep vertical ground heat exchanger (VGHE) can keep the surface 
of the floor at the night heating thermostat of 15°C for the bedroom even if the outdoor temperature 
falls below 10°C.   
The  function  of  the  RC  could  be  replaced  by  water  ways  constructed  into  the  inside  face  of 
commercially manufactured metallic‐clad polystyrene panels. This building‐integrated water radiator 
could become building materials for affordable comfortably heated homes.   
References 
1.
2.
3.
4.
5.
6.
7.
Qian Wang, Adnan Ploskić, Sture Holmberg Retrofitting with low-temperature heating to achieve energy-
demand savings and thermal comfort Energy and Buildings, Volume 109, 15 December 2015, Pages 217-
229
Dietrich Schmidt, Anna Kallert, Markus Blesl, Svend Svendsen, Hongwei Lid, Natasa Nord and Kari Sipilä.
Low Temperature District Heating for Future Energy Systems. Energy Procedia, Volume 116, June 2017,
Pages 26-38
Mats Dahlblom, Birgitta Nordquist, Lars Jensen Evaluation of a feedback control method for hydronic
heating systems based on indoor temperature measurements Energy and Buildings, Volume 166, 1 May 2018,
Pages 23-34
Matjaž Prek, Gorazd Krese Experimental analysis of an improved regulation concept for multi-panel heating
radiators: Proof-of-concept Energy, Volume 161, 15 October 2018, Pages 52-59
Petr Ovchinnikovab, Anatolijs Borodiņecsc, RenārsMillersc (2017) Utilization potential of low temperature
hydronic space heating systems in Russia Research article Journal of Building Engineering, Volume 13,
September 2017, Pages 1-10 https://doi.org/10.1016/j.jobe.2017.07.003
M. Jangsten, J. Kensby, J. -O. Dalenbäck, A. Trüschel Survey of radiator temperatures in buildings supplied
by district heating Energy, Volume 137, 15 October 2017, Pages 292-301
Jonn Are Myhren and Sture Holmberg Performance evaluation of ventilation radiators Applied Thermal
Engineering, Volume 51, Issues 1–2, March 2013, Pages 315-324
Zero-energy Sustainable Heating and Cooling System Exploration in Cool and Hot Climates
280