Hi Farzad

there are numerous reports of this nature in the literature, one example being: http://journals.cambridge.org/article_S0007114589000267 or http://ajcn.nutrition.org/content/49/6/1146.short by Ceesay et al/westerterp et al back in the 80's. 

there are also plenty moving forward in time, fast forward to  2005: Prediction of energy expenditure from heart rate monitoring during submaximal exercise, by Keytel et al (http://shapeamerica.tandfonline.com/doi/abs/10.1080/02640410470001730089), who successfully 

You can correlate the % of HRmáx with VO2máx so you calcule using the MET and Kcal/min formulas.

Take a look.

http://www.scielo.br/pdf/rbme/v19n2/en_13.pdf